New York State took population name censuses at ten year intervals from 1825 to 1875, in 1892, and again from 1905 to 1925. The first census of the United States was taken in 1790 and has been repeated every 10 years since then as mandated by the U.S. Constitution to determine representation in the U.S. House of Representatives.

Beginning with the 1850 census, the names of all persons in a household were recorded. Before that time (1790-1840) only the name of the head of household was taken. The information collected each census year has grown over time, and census records are now goldmines of genealogical information. Libraries in Monroe County provide access to census information in a variety of ways, from microfilm to handwritten index cards to online databases. This list below describes the types of information available at Monroe County Libraries.

• Summary of Census Holdings in the Local History Division of the Rochester Public Library.
• Software Holdings at the Ogden Farmers' Library.
• Microfilm Holdings at the Ogden Farmers' Library.
• Ancestry.com - The Local History Division of the Rochester Public Library and the Ogden Farmers' Library subscribe to this database, which must be used inside the library.