The Decennial Census, mandated by the Constitution, counts the population of the United States for Congressional redistricting. It occurs every ten years ending in a zero. Over time, the Decennial Census started to collect socio-economic information useful to create legislation and understand the population of the country.
The Decennial Census of Population and Housing is taken every year ending in a zero. The most recent was taking in 2010.
Census Explorer, a partnership between Social Explorer and the Census Bureau, allows researchers to map data. Visualize statistics from the most recent set from the American Community Survey, as well as the 1990 and 2000 Decennial Censuses.