Statewide North Dakota Census records that exist are 1850 (as Pembina County, Minnesota Territory), 1860 (as unorganized Dakota), 1870 (as Dakota Territory; special 1885), 1880, 1890 (fragment, see below), 1900, 1910, 1920, 1930 and 1940.
The Iowa Territory census of 1836 contains the first federal census records that included residents of what is now North Dakota. The following census documents are available on microfilm at the State Historical Society of North Dakota’s Historical Research Library, as well as at the North Dakota State Archives: 1850 Pembina County Minnesota Census, 1860, 1870, and 1880 Dakota Territory Censuses, 1890 Union Veterans and Widows Census, 1900 federal Census, Including Soundex, 1910 Federal census.
The 1870 and 1880 Dakota Territory agricultural schedules have been microfilmed. The South Dakota State Historical Society has them on file.
The State Archives and Historical Research Library holds the 1857 state census of Pembina County, but it’s important to note that Pembina County was part of Minnesota Territory at that time.
In 1885, a special pre-statehood census was taken of the area that is now North Dakota. Part of that census is still extant. It included a special return featuring information about mortality and veterans. It is available via inter-library loan and can be found on file at the State Archives and Historical Research Library, along with the 1915 and 1925 North Dakota state census records, which are not indexed.
Each of the North Dakota Native American reservations took censuses at various points. Many of those records are still extant, and most are on file at the State Archives and Historical Research Library, although not all of them are indexed. The records on file there include: Fort Totten Reservation – 1885 to 1905, 1910 to 1939, Fort Berthold Reservation – 1889 to 1893, 1895 to 1939, Turtle Mountain Reservation – 1885 to 1905 (with Fort Totten Reservation), 1910 to 1939 , Digger Indians – 1899 to 1904, 1915 to 1920.
The Following records are available at the Kansas City National Archives-Central Plains Region: Standing Rock Reservation – 1885 to 1913, 1915 to 1939
Searchable North Dakota Census Databases and other Helpful Links