Today the National Archives launched the 1940 Census online. This is the first time the census has ever been available online in its entirety!
The first census was taken in 1790, and has continued to be conducted every 10 years. Until 1840, Federal judges and marshals throughout the U.S. administered the census. In 1840, Congress passed the Census Act which created a central office for the census that opened and closed for each counting. Finally in 1902, Congress passed this act creating a permanent Census Office within the Federal government.
H.R. 198, a bill to establish a permanent Census Bureau, 12/2/1901, HR57A-B1, Records of the U.S. House of Representatives