Slavery in the colonial history of the United States refers to the institution of slavery as it existed in the European colonies which eventually became part of the United States. Slavery developed due to a combination of factors, primarily the labour demands for establishing and maintaining European colonies, which had resulted in the Atlantic slave trade. Slavery existed in every European colony in the Americas during the early modern period, and both Africans and indigenous peoples were victims of enslavement by European colonizers during the era.

The United States of America, commonly known as the United States or America, is a country primarily located in North America. It is a federation of 50 states, a federal capital district, and 326 Indian reservations. Outside the union of states, it asserts sovereignty over five major unincorporated island territories and various uninhabited islands. The country has the world's third-largest land area, second-largest exclusive economic zone, and third-largest population, exceeding 334 million.