New York City was the antebellum manufacturing, commercial and shipping center of the United States, and many New York firms found their greatest market in the slave-holding States. This was true of those selling the cheap cotton goods for slave clothing, and luxury items earmarked for the planters. The trade with the South was so great that many companies advertised themselves as “exclusively for the Southern trade.” Manhattan bankers had ready-money at low interest for planters, Northern or Southern, wanting to buy more land to plant cotton for which slaves were needed.
New York passed progressive emancipation bills in the early 1800s and many were sold to Southern planters, but slaves still existed within the State in the 1840s. It is noteworthy that the Duke of York, for whom the city was named, governed the Royal African Company until he took the throne as James II
New York’s Forgotten Past
“In colonial times New York State slave owners were legion, and slavery continued there until just twenty years before the beginning of the Civil War. New York had the largest and most important slave system in colonial times north of the Mason-Dixon Line. The State provided an excellent example of urban slavery, where slaves [worked] next to free whites and acquired a variety of special skills.
The Dutch West India Company introduced slaves into New Netherlands in 1626. They were imported to New York to work on the farms, public buildings, and military works for which free workers were not available. It is doubtful whether New Netherlands would have survived without these slaves, for they provided the labor which ultimately transformed the colony from a shaky commercial outpost into a permanent settlement.
When the British captured New Netherlands in 1664, slavery continued and the slave population multiplied. Slaves were concentrated in New York City and surrounding counties. By 1746 Negro slaves accounted for 15 percent of the total New York population.
[The British occupation of southern New York during the Revolution] thoroughly disrupted slave relations. The British offered freedom to slaves who sought asylum with them . . . [which] undermined the slave system in New York.
In 1790 New York had 21,324 slaves, which increased ten years later to 30,343, the highest number of slaves New York ever possessed. By 1820, New York’s slightly more than 10,000 slaves showed a 33 percent decrease since 1810. By 1830, 75 slaves remained in the State, ten years later there were only four.”
(The Secession Movement in the Middle Atlantic States, William C. Wright, Fairleigh Dickinson University Press, 1973, excerpts pp. 165-166)