The United States Census 1820 was the fourth census in the United States since 1790 . As a result of the census, a population of 9,638,453 inhabitants was determined for the USA on August 7, 1820, of which 1,538,022 were slaves . The data contain information on the name of the head of the family, number of free white and colored persons (men and women, by age group), number of free persons, number of slaves, foreigners ("foreigners not naturalized"), employment by sector (agriculture, Trade, craft), city or district, or place of residence or residential district, persons who do not pay taxes.
The state population figures from the 10-year United States censuses are key to determining the number of representatives from those states in the United States House of Representatives . The adjustment is usually made in the next but one Congress after a census.
Most populous cities
The 50 most populous cities in the United States by population in 1820.