United States Census, 1820

The 1820 United States census was the fourth census conducted in the United States. It was conducted on August 7, 1820. The 1820 census included six new states: Louisiana, Indiana, Mississippi, Illinois, Alabama and Maine. There has been a district wide loss of 1820 census records for Arkansas Territory, Missouri Territory, and New Jersey. The total population was determined to be 9,638,453, of which 1,538,022 were slaves. The center of population was about 120 miles (193 km) west-northwest of Washington in Hardy County, Virginia (now in West Virginia). This was the first census in which any states recorded a population of over one million—New York, Virginia, and Pennsylvania—as well as the first in which a city recorded a population of over 100,000—New York. Also, in this census and the 14 subsequent ones, New York was the most populous state until being superseded by California in the 1970 census.