The Census Bureau is part of the U. S. Department of Commerce. The U. S. Census Bureau is overseen by the Economics and Statistics Administration (ESA) within the Department of Commerce. The Economics and Statistics Administration provides high-quality economic analysis and fosters the missions of the U. S. Census Bureau and the Bureau of Economic Analysis.
The Census Bureau's mission is to serve as the leading source of quality data about the nation's people and economy - honoring privacy, protecting confidentiality, sharing its expertise globally, and conducting its work openly.
The first Federal Population Census was taken in 1790, and has been taken every ten years since. However, data from recent censuses are not available after 1940 because of a 72-year restriction on access to the Census. Most researchers find it most helpful to begin with the 1940 Census and work backwards to locate people in earlier generations.