High Quality Content by WIKIPEDIA articles! The Twenty-second United States Census, known as Census 2000 and conducted by the Census Bureau, determined the resident population of the United States on April 1, 2000, to be 281,421,906, an increase of 13.2% over the 248,709,873 persons enumerated during the 1990 Census. This was the twenty-second federal census and was at the time the largest civil administrative peacetime effort in the United States.