The "peculiar institution” of slavery cuts a swath through the heart of American history, with effects that lasted long after its abolition by Lincoln's Emancipation Proclamation (1863) and the Thirteenth Amendment to the U.S. Constitution (1865). African slavery on the mainland can be traced back almost to the beginnings of European settlement and was practiced in all parts of British colonial America. But after the Revolution the division of these former colonies into groups of "free” and "slave” states laid the basis for secession and the Civil War (1861–1865), the costliest conflict in American history. The lasting legacies of slavery and the Civil War for the South and for African Americans are still debated in the new millennium, with passions barely diminished by time.

In one sense the statistical record of this history is abundant, though many aspects of slavery's human reality lie beyond the reach of quantitative measurement. The demographic history of African slaves during the colonial period – arrivals and population growth – has been pieced together by scholars from a wide if heterogeneous array of surveys and commercial reports. Beginning with the first federal census of 1790, the slave population may be studied in remarkable geographic detail, by cities and counties as well as states. As the scope of census inquiries expanded in 1840, 1850, and 1860, the surveys of agriculture and manufacturing have formed the primary basis for a flourishing literature on the economics of slavery in the late antebellum period. These sources may be supplemented by others, such as the records of transactions in slaves at leading markets such as New Orleans, probate inventories, and surviving business and plantation accounts. The present chapter presents only a small fraction of the full archival record, focused on basic series that convey a sense of the evolution of the institution and the slave population over time.

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Its importance in American history notwithstanding, slavery did not originate in the colonies that became the United States, nor did the colonies play a particularly significant role in the transatlantic slave trade. Highly developed systems of slavery existed in ancient Greece and Rome and persisted in medieval Europe, and several different forms of slavery were practiced for centuries in Asia, Africa, and the Americas before the arrival of Columbus.¹  Perhaps a million African slaves were transported to South America on Portuguese and Spanish ships before the first "twenty and odd Negroes” arrived in Virginia in 1619. Over the entire history of the transatlantic slave trade, no more than 8 percent of the coerced African migrants came to mainland North America. The much larger U.S. share in the hemispheric slave population of 1860 (approximately 50 percent) is attributable to the very different demographic experience of slaves in North America than elsewhere in the New World.²

By 1619, slavery had been on the decline in England (as elsewhere in western Europe) for centuries. Perhaps for this reason, the legal definition of slavery as perpetual servitude of blacks and their progeny was not fully established in the Chesapeake Bay region until the 1660s. A number of the first generation of African Americans were regarded as "servants” eligible for freedom after a certain term of years, by analogy to the indentured laborers who formed the majority of the workforce in the Upper South during the seventeenth century. In 1664, however, Maryland declared that all blacks held in the colony, and all those imported as slaves in the future, would serve for life, as would their children and later generations; Virginia's policy became equally clear by the end of that decade (Galenson 1996, p. 165). Both the practice and the legal definition of slavery became established in relatively similar form throughout English America.

Slavery was not inflicted exclusively on Africans. During the early settlement of South Carolina, for example, native peoples were frequently captured and sold to planters in the West Indies. With the rise of rice and naval stores as exports after 1700, larger numbers of enslaved Indians were kept in the low country, reaching a peak of roughly 2,000 by 1720 (Menard 1996, p. 287). In this instance, Indian slavery collapsed through the legislative intervention of the Carolina assembly, which was fearful of triggering new outbreaks of war with regional tribes. More broadly, the demographic devastation experienced by the native population made its members unsuitable candidates for enslavement (see the essay on American Indians in Chapter Ag).

Only at the very end of the seventeenth century did the inflow of African slaves become substantial. As of 1690, blacks constituted less than 15 percent of the population in Virginia and Maryland, reflecting the fact that the first two generations of Chesapeake tobacco planters primarily used the labor supplied by white indentured servants (Table Eg1–59). Between 1690 and 1710, the pattern changed radically. Data newly compiled by Lorena Walsh (2001) show that the number of slaves imported into Virginia and Maryland averaged about 750 per year during 1698–1703, then surged to 1,500 per year after 1720 and remained high until the American Revolution (Table Eg214–216). The shift may also be observed in the composition of colonial populations: in Virginia, the proportion of blacks rose from 7 percent in 1680 to 30 percent in 1720 (Table Eg1–59). The reasons for this "transition from servants to slaves” have been intensively studied by economic historians (Gray and Wood 1976; Menard 1977; Galenson 1981). The primary forces may be identified as rising scarcity in the supply of servants; improved life expectancy among African Americans, enhancing their value as slaves for life; and booming demand for Chesapeake tobacco after 1700.

The number of slaves imported into the Lower South colonies of South Carolina and Georgia was not as high, but the slaves' share of the population was much larger. The South Carolina population was more than one third black in 1690, and two thirds black by 1730 (Table Eg1–59). The expansion of Georgia's slave population was delayed by its designation in 1733 as a debtor's colony within which slavery was prohibited. Slaves quickly flowed into Georgia when the restriction was lifted in 1750, pushing the black share in the population above 40 percent by 1770 (Table Eg1–59). During the years 1768–1772, for which detailed figures on the trade are available, more than 40 percent of all imported slaves were sent to Georgia (Table Eg201–213). The contrast in the relative prominence of slavery between the Upper South and the Lower South reflects the adverse health conditions and arduous labor requirements of lowland rice cultivation, whereas tobacco farming continued to be attractive to free family farmers as well as to slave owners.

Although the slave population was highly concentrated in the Southern colonies, it is important to note that slavery existed in all of the colonies, persisting until after the Revolution. The figures show more than 3,000 blacks in Rhode Island in 1748, 9.1 percent of the population; 4,600 blacks in New Jersey in 1745, 7.5 percent of the population; and nearly 20,000 blacks in New York in 1771, 12.2 percent of the population (Table Eg132–140 and Table Eg155–161, Table Eg162–168). Most of these blacks are presumed to have been slaves, though the colonial censuses were rarely explicit about status. For an exception, see the 1755 figures for Maryland reported in Table Eg169–181, which indicate that 99 percent of the 42,061 recorded blacks were slaves, though only 60 percent of the 3,608 mulattos were slaves.

Emancipation measures in the Northern states followed in the wake of the Revolution, beginning with Vermont in 1777. But in New York and New Jersey, the struggle to pass an emancipation act was contentious. New York did not do so until 1799, New Jersey not until 1804 (see Table Bb-A). Most of the Northern emancipations were gradual, often applying only to children and only after lengthy periods of "apprenticeship.” Thus, one finds enumerations of Negro slaves in Northern states even into the 1840s (Table Bb1–98). The most remarkable case of lingering Northern slavery was in New Jersey, which reported 236 slaves in 1850, and 18 as late as 1860 (series Bb15).³

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Despite the protracted character of Northern abolition, by the 1790s the country was clearly divided into two sections, one slave and one primarily free, each approximately equal in population and area at the outset. The Northwest Ordinance of 1787 prohibited slavery in the area north of the Ohio River, thus extending the division into the western territories then undergoing rapid settlement. The final step in defining the institutional structure of the era occurred in 1807, when Congress terminated the African slave trade, the constitutional proscription on interference with the trade having expired. After the final influx of Africans between 1793 and 1807, associated with the emergence of cotton as a major export, the Southern states acquiesced in this prohibition. Thus, from this date onward, the growth of the slave population was almost entirely due to natural increase.

Despite this restriction, the slave population grew very rapidly, averaging more than 2 percent per year across the half-century prior to the Civil War (Table Aa145–184 and Table Bb1–98). This demographic history was unique among slave systems in the New World (Fogel 1989, pp. 114–53), and was surely not unrelated to the South's willingness to accede to the cessation of the African trade in 1807. Among many implications of the reliance on natural increase, one may note the strikingly equal gender balance of the slave population (Table Aa2093–2140). In 1820, male slaves outnumbered females slightly, at 51.2 percent of the total. By 1840, however, the male and female totals differed by no more than one tenth of 1 percent. This balance is in contrast to slave regimes in which the African trade remained open, in which men typically outnumbered women by large margins. However, the detailed state data found in Table Bb129–166 show somewhat larger numbers of women than men in Eastern states such as Georgia and South Carolina, which some have interpreted as a "division of labor” between slave-exporting and slave-importing states (Sutch 1975).

Many dimensions of American slavery may be illustrated with demographic data. Table Bb1–98 shows the geographic shift of the slave population from the older Eastern states (Virginia, North and South Carolina, and Georgia) to the newer cotton-growing states farther to the west (Alabama, Mississippi, Louisiana, Arkansas, and Texas). Thus Mississippi's slave population increased from 17,088 in 1810 to 436,631 in 1860, while Virginia's grew only from 392,516 to 490,865 over the same period. Nonetheless, one could describe the slave system as "declining” only in Maryland and Delaware during the antebellum era. In Delaware the slave population fell continuously after 1790, so that fewer than 2,000 remained in 1860. In Maryland the decline was more gradual, but by 1860 the number of free blacks nearly equaled the number of slaves.

The demographic data do not tell us what fraction of this forced migration took the form of transactions in slave markets, as opposed to migration of intact plantation groups. Because these magnitudes must be estimated by indirect means, it is not surprising that quantitative historians have reached widely varying conclusions on this issue (Fogel and Engerman 1974, pp. 44–52; David, Gutman, et al. 1976, pp. 99–133; Tadman 1989, pp. 25–31). The most recent estimates suggest that the relocation was about equally divided between the two modes (Pritchett 2001).

Despite the examples of Delaware and Maryland, we can say with reasonable confidence that the geographic shift in the slave population was not primarily the result of the emancipation of slaves in the Eastern states, a process known as "manumission.” The free black population did experience a sharp increase shortly after the Revolution, partly as the result of wartime measures by the British, and partly because the postwar ethos of freedom seemed for a time to be spreading even in the South. In Virginia, the number of free blacks grew from 12,866 in 1790 to 30,570 in 1810, while in Maryland nearly one fourth of the black population was free by the latter year (Table Bb1–98). Thereafter, however, the share of free blacks in the black population failed to increase, drifting downward from 13.2 percent in 1820 to 11.0 percent in 1860 (Table Aa145–184). Within five years of the Nat Turner slave rebellion of 1831, nearly all the Southern states prohibited the freeing of slaves without legislation or court approval, frequently requiring that freed slaves leave the state. By the 1850s, Texas, Mississippi, and Georgia barred manumission altogether. When the census tabulated manumissions in 1860, it counted only 3,018 in a slave population of four million, or fewer than one per thousand (Table Bb219–235). By 1860, fewer than 3 percent of blacks were free in every one of the states of the Lower South (Table Bb1–98).

Another dimension of slave demography is the distribution of slaves among slaveholding units of various sizes. By comparison with slave systems elsewhere in the New World, ownership in the United States was widely dispersed. The 1790 Census figures (not compiled until more than a century later) allow comparisons across seventy years (Table Bb196–208). In the face of historic changes in the geography of slavery (from Southeast to Southwest) and in the primary slave crops (from tobacco to cotton), the size distribution of slaveholdings remained remarkably constant. Only 0.3 percent of the owners held more than 100 slaves in 1790, and by 1860 this proportion had increased merely to 0.6 percent. Although the mean slaveholding varied considerably from state to state – in 1850, for example, from 7.1 in Tennessee to 15 in South Carolina – within each state the average drifted up only slowly over time. The primary split in Southern white society was between slave owners and non–slave owners. As of 1860, in the cotton-growing areas approximately one half of the farms did not own slaves; for the South as a whole, the percentage of slaveowning families declined from 36 in 1830 to 25 in 1860 (Wright 1978, pp. 24–42).

Although slave ownership status was widely dispersed, the matter of scale looked rather different from the perspective of the slaves. Inequality of holdings was such that the "average slave” worked in a relatively large unit. In the cotton-growing areas of 1860, for example, one third of the slaves were part of holdings larger than 50 (Wright 1978, p. 31).

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Rich statistical sources in combination with the enduring and provocative character of the subject have generated a robust and sometimes contentious literature on the economics of American slavery. Beginning with Conrad and Meyer (1958), historical economists have attempted to resolve long-standing debates over the "profitability” of slavery by subjecting the available data to rigorous statistical analysis in light of more precisely defined economic concepts. A core input for most of this research is information on the prices at which slaves were bought and sold in the major markets of the South.

Table Bb209–214 presents four series on the course of slave prices from the early nineteenth century until the Civil War. Series Bb209 is attributable to Ulrich Phillips (1918, 1963), an eminent Southern historian of the early twentieth century and a pioneer in the quantitative study of slavery. The series applies to "prime field hands” and was based on invoices of slave sales, but Phillips never published a precise statement of his sample or selection criteria. Subsequent researchers have concluded that the Phillips price series for New Orleans has an upward bias. Series Bb210, attributable to Stanley L. Engerman, is based on a systematic sample of slave sales in New Orleans from 1804 through 1861, ranging from 2.5 to 5 percent of sales of "males aged 18 to 30, fully guaranteed as without physical or other infirmity.” The third series, attributable to Laurence J. Kotlikoff (1979), is from the same underlying source, but pertains to all men 21 to 38 years of age, regardless of their physical condition.

Despite their differences, all three New Orleans series show similar trends and fluctuations across the full period (see Figure Bb-A): an upward surge after 1807, with periods of decline after the peaks of 1819–1820 and 1837–1839; from the trough in the mid-1840s, slave prices surged throughout the 1850s to all-time highs on the eve of secession (approximately $1,500 for a prime field hand). The fluctuations generally follow swings in the business cycle, particularly British demand for American cotton. The overall trend in slave prices is strongly positive.

Following Phillips, some scholars have argued that slavery had become "unprofitable” by the end of the 1850s because slave prices had then reached record high levels. It was pointed out very early by Yasukichi Yasuba (1961) and Richard Sutch (1965), however, that period fluctuations in slave prices had no particular significance for the long-term real returns to investments in slavery. Similar price swings had occurred twice before in the antebellum period. The deeper significance of this evidence is that slaves were priced, and slave markets were conducted, largely on the basis of expected profitability. Beginning with Conrad and Meyer (1958), virtually all economic studies have confirmed this finding.⁴

Another aspect of the market-oriented nature of American slavery is the structure of slave prices, as opposed to the level and trend in average prices over time. An illustration of price structure is the age–sex price profile presented in Table Bb215–218, developed by Robert W. Fogel and Stanley L. Engerman (1974) from data in probate records. The profiles display a systematic relationship between age and price, with the male profile rising above the female in the late teen years, followed by a peak in both profiles in the late twenties and then a decline. To be sure, these profiles are averages across many hundreds of observations; individual sale prices show considerable dispersion on either side of the line. But detailed statistical analyses show that much of the dispersion can be accounted for by observable traits of the slaves (such as skills or physical defects) or features of the transaction (such as guarantees or credit extension) (Kotlikoff 1979).

Another meaningful approach to measuring the economic returns to slave owners is to focus on the accumulation of wealth in the form of slave value. This is the objective of series Bb212, the "average value of a slave” economywide, which adjusts the prime field hand price for the age, sex, location, and skill of the total slave population each year. In combination with annualized estimates of the slave population (series Bb214), this series allowed Sutch to generate estimates of the overall growth in the stock of slave wealth (series Bb213). Viewed in this way, the enrichment of the slave owners was vast: from $291 million in 1805 to more than $3 billion in 1860, a tenfold increase. Slave capital represented 44 percent of all wealth in the cotton-growing states in 1859, the largest single component (Ransom and Sutch 1988, pp. 138–9).

It hardly needs saying that the high profitability of slavery to the owners did not necessarily enhance the well-being of the other members of the Southern population. This point is clearest in the case of the slaves, who were denied both the immediate fruits of their labor and opportunities for self-advancement through the acquisition of skills and education. But nonslaveholding whites were also affected by the economics of slavery, through competition in land and product markets, and because of slavery's effects on the course of development of the regional economy. Ransom and Sutch (1988) argue that adverse economic effects were the direct consequence of the successful accumulation of wealth in the form of slave value. As in the standard macroeconomic model depicting the burden of public debt, the rise of slave value "crowded out” other forms of wealth in Southern portfolios, reducing other forms of real capital formation. On these grounds, Ransom and Sutch attribute the South's relative lag in transportation, manufacturing, and human capital investment to the effects of capitalization of slave value.

Another developmental issue that has received academic attention is the effect of slavery on urbanization, and vice versa. Table Bb99–128 presents census data on the free and slave populations of ten Southern cities from 1820 to 1860. Although the overall share of the slave population in cities was not large, a port city such as Charleston held a substantial number of slaves (12,652) as of 1820. As Mississippi River commerce grew after 1820, New Orleans became the largest slaveholding city in the country (at 23,448 in 1840). Most notably, however, the table shows that between 1820 and 1860, slaves declined as a share of the population in every one of the ten cities listed, the slave population falling absolutely in six of the ten. Richard Wade (1964) attributes the decline of urban slavery to the growing costs of maintaining the necessary discipline in an urban setting. Escape was much easier than in the countryside, the communities of free blacks often providing refuge and assistance to runaways. Slaves in the cities generally had greater personal freedom, often being hired out rather than employed by their owners, sometimes even being allowed to arrange their own employment. Altogether, according to Wade, the institutional and cultural supports for slavery were being undermined in the cities of the South.

An alternative interpretation, advanced by Claudia Goldin (1976), is that slaves were largely pulled rather than pushed out of the cities because of the strong demand for labor in agriculture, especially during the cotton boom of the 1850s. Because slave prices were rising in both urban and rural markets, the econometric evidence tends to support the Goldin thesis. To be sure, slavery might have required extensive restructuring if the economy of the South had shifted strongly in an urbanized direction. That such a course was feasible is indicated by the exceptional case of Richmond, the slave population of which expanded even in the 1850s because of the growth of its iron and tobacco industries based on slave labor (series Bb117).

The hypothetical course of slavery in the absence of the Civil War cannot be objectively determined on the basis of historical data alone. On the one hand, the extremely limited number of fugitive slaves recorded in 1850 and 1860 (Table Bb236–251) suggests that the institution was not crumbling. Although fears of slave revolts were ubiquitous in the slaveowning South, the compilation of actual cases in Table Bb252–254 does not point toward acceleration of rebellious activity, even as the crisis over slavery came to dominate national politics. Although this sort of evidence is undoubtedly imperfect in many ways, it is sufficient to suggest that the confidence of slave owners in the future of their institution – reflected in the high slave prices of 1860 – had an objective basis.

On the other hand, by 1860 the historical trend had been toward abolition for nearly a century (see Table Bb-A), and there is reason to think that many slaves were aware of this trajectory at some level. Once the war began, plantation discipline proved very insecure whenever fighting drew near, so that slavery did indeed collapse over broad areas of the South as the Union army advanced. Thus the apparent stability of slavery in 1860 may have masked an underlying vulnerability that could not have been suppressed indefinitely, although how long it might have taken in the absence of the Civil War remains uncertain.

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[TABLE Bb-A Chronology of emancipation: 1761–1888]

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Series Bb209–210 and Series Bb212.

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Conrad, Alfred H., and John R. Meyer. 1958. "The Economics of Slavery in the Ante-Bellum South.” Journal of Political Economy 66 (April): 95–130.

Curtin, Philip D. 1969. The Atlantic Slave Trade: A Census. University of Wisconsin Press.

David, Paul A., Herbert G. Gutman, et al. 1976. Reckoning with Slavery.  Oxford University Press.

Drescher, Seymour, and Stanley L. Engerman. 1998. A Historical Guide to World Slavery. Oxford University Press.

Eltis, David. 2000. The Rise of African Slavery in the Americas. Cambridge University Press.

Fogel, Robert W. 1989. Without Consent or Contract: The Rise and Fall of American Slavery. Norton.

Fogel, Robert W., and Stanley L. Engerman. 1974. Time on the Cross: The Economics of American Negro Slavery. Little, Brown.

Galenson, David W. 1981. White Servitude in Colonial America. Cambridge University Press.

Galenson, David W. 1996. "The Settlement and Growth of the Colonies.” In Stanley L. Engerman and Robert E. Gallman, editors. The Cambridge Economic History of the United States. Cambridge University Press.

Goldin, Claudia. 1976. Urban Slavery in the South, 1820–1860. University of Chicago Press.

Gray, Ralph, and Betty Wood. 1976. "The Transition from Indentured to Involuntary Labor in Colonial Georgia.” Explorations in Economic History 13 (October): 353–70.

Hodges, Graham Russell. 1997. Slavery and Freedom in the Rural North: African Americans in Monmouth County, New Jersey, 1665–1865. Madison House Publications.

Kotlikoff, Laurence J. 1979. "The Structure of Slave Prices in New Orleans, 1804 to 1862.” Economic Inquiry 17: 496–517.

Menard, Russell R. 1977. "From Servants to Slaves: The Transformation of the Chesapeake Labor System.” Southern Studies 16 (Winter): 355–90.

Menard, Russell R. 1996. "Economic and Social Development of the South.” In Stanley L. Engerman and Robert E. Gallman, editors. The Cambridge Economic History of the United States. Cambridge University Press.

Phillips, Ulrich B. 1918. American Negro Slavery. Appleton.

Phillips, Ulrich B. 1963. Life and Labor in the Old South. Little, Brown. First published 1929.

Pritchett, Jonathan B. 2001. "Quantitative Estimates of the United States Interregional Slave Trade, 1820–1860.” Journal of Economic History 61 (June): 467–75.

Ransom, Roger, and Richard Sutch. 1988. "Capitalists without Capital: The Burden of Slavery and the Impact of Emancipation.” Agricultural History 62 (Summer): 133–60. Reprinted in Morton Rothstein and Daniel Field, editors. 1993. Quantitative Studies in Agrarian History.  Iowa State University Press.

Sutch, Richard. 1965. "The Profitability of Ante Bellum Slavery – Revisited.” Southern Economic Journal 31 (April): 365–77.

Sutch, Richard. 1975. "The Breeding of Slaves for Sale and the Westward Expansion of Slavery, 1850–1860.” In Stanley L. Engerman and Eugene D. Genovese, editors. Race and Slavery in the Western Hemisphere: Quantitative Studies. Princeton University Press.

Tadman, Michael. 1989. Speculators and Slaves: Masters, Traders and Slaves in the Old South. University of Wisconsin Press.

Wade, Richard C. 1964. Slavery in the Cities. Oxford University Press.

Walsh, Lorena S. 2001. "The Chesapeake Slave Trade: Regional Patterns, African Origins, and Some Implications.” William and Mary Quarterly, 3rd series, 58 (January): 139–70.

Wright, Gavin. 1978. The Political Economy of the Cotton South. Norton.

Yasuba, Yasukichi. 1961. "The Profitability and Viability of Plantation Slavery in the United States.” Economic Studies Quarterly 12: 60–67. Reprinted in Robert W. Fogel and Stanley L. Engerman, editors. 1972. The Reinterpretation of American Economic History. Harper and Row.

Zilversmit, Arthur. 1967. The First Emancipation: The Abolition of Slavery in the North. University of Chicago Press.

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