Final answer:
Around 1760, approximately 350,000 slaves lived in the 13 colonies, making up about 14% of the total population of 2.5 million. With enslaved Africans present in every colony, the prevalence of slavery varied significantly, with higher concentrations in the South and significant numbers also in Northern urban and agricultural areas.
Step-by-step explanation:
During the American Revolution, slavery was a national institution, with enslaved Africans living throughout the thirteen colonies. Although slavery was more predominant in the South, the North had a significant slave presence as well. By 1760, around 350,000 enslaved blacks were living in the colonies, with the majority in Virginia and Maryland, and significant populations in South Carolina, Georgia, New York, and New Jersey. When considering the overall population of the colonies at this time, which was about 2.5 million, enslaved people constituted roughly 14% of the total population. This percentage, however, was not uniformly distributed across the colonies. For instance, in South Carolina, enslaved Africans outnumbered Europeans by 1720, indicating a much higher dependency on and prevalence of slavery in the South.
The percentages varied from one colony to another and also depended on whether the populations were in urban centers, agricultural areas along the seacoast, or major cities. For example, in Connecticut, Massachusetts, and Rhode Island, slaves made up significant portions of the population, with figures like 30% in South Kingston and 10% in Boston. By contrast, in the Chesapeake colonies and the Low Country of South Carolina and Georgia, slavery had become even more ingrained into the economy and social structure by the late eighteenth century, laying the groundwork for the United States' continued reliance on slave labor post-Revolution.