The New Student's Reference Work (1914)
“ In 1849 North Dakota east of the Missouri became part of Minnesota for a time, and the area west of the river was made a part of Nebraska Territory. In 1851 to the Federal government was ceded part of the lands held by the Sioux Indians, and these lands were thrown open for settlement. In 1861 Dakota Territory was created, part of Montana and part of Wyoming being included in it; while two years later, on the creation of Idaho Territory, the Dakotas assumed almost their present area, and in 1889 they were separated, forming North Dakota and South Dakota. ”
