Final answer:
Virginia had the largest enslaved population in the first half of the nineteenth century, with historical records from the Revolutionary era indicating about 145,000 enslaved individuals there.
Step-by-step explanation:
The state that had the largest enslaved population in the first half of the nineteenth century was Virginia. This is evidenced by historical records indicating that around the time of the American Revolution, Virginia and Maryland combined had approximately 145,000 enslaved individuals. Furthermore, Virginia's laws and its economic dependency on slavery further substantiate the large number of enslaved people in the state. The growth of the enslaved population in the South, including Virginia, can be attributed to the cotton boom in the 1830s, despite the ban on international slave trade in 1808.
Comparatively speaking, the states of New York and Massachusetts had much smaller enslaved populations. While New York did have slaves, it gradually phased out slavery with the last individuals being emancipated in the late 1820s. Massachusetts, on the other hand, had technically freed all enslaved people with its constitution in 1780, yet some court cases were still necessary to reinforce this legal status.
By the mid-19th century, the institution of slavery was much more prominent in the Southern states than in the Northern states. Consequently, Virginia's enslaved population during the first half of the 19th century significantly outnumbered that of the more northern states like New York and Massachusetts.