Minnesota
- Manomin County, Minnesota (1857–1858) disorganized and shifted between three counties it became part of Anoka County in 1869-1870
- Monongalia County, Minnesota (1861–1870) merged with Kandiyohi County
- Pembina County, Minnesota Territory (1849–1858, reconstituted as Pembina County, Dakota Territory in 1861, eventually reduced to present-day Pembina County, North Dakota.)
Read more about this topic: List Of Former United States Counties