From the Guide to 2010 State and Local Census Geography – Minnesota – History:

The area of Minnesota was partially included in the original territory of the United States, being part of lands ceded by four states to the United States and designated in 1787 as the "Territory northwest of the River Ohio." The United States acquired the remainder of the area from France in 1803 as part of the Louisiana Purchase and by a convention signed with Great Britain in 1818 that extended the northern boundary along the 49th parallel westward from a line drawn due north from the source of the Mississippi River. Minnesota Territory was organized on March 3, 1849, from unorganized area formerly within Iowa and Wisconsin territories. The territory included all of the present-day state of Minnesota, the eastern part of North Dakota and South Dakota, and a small part of Nebraska. Minnesota Territory was reduced in size in 1854 when the portion in present-day Nebraska was included in Nebraska Territory. Minnesota was admitted to the Union on May 11, 1858, as the 32nd state, with generally the same boundary as the present state. The remaining part of Minnesota Territory was not assigned until the organization of Dakota Territory in 1861; in 1860 census reports, the area was identified as "unorganized Dakota."

Census data for Minnesota are available beginning with the 1850 Census. The 1850 population is for the entire area of Minnesota Territory, including population in area not in the present state.

Data for the legally established state of Minnesota are available beginning with the 1860 Census.