The Twenty-Secon 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 the largest single civil administrative peacetime effort in the history of the United States.