Fort Atkinson State Preserve is a state preserve of Iowa, USA, containing the remnants of Fort Atkinson, a U.S. Army frontier post created to keep the peace between various Native American tribes as well as prevent white settlers from encroaching on Indian lands.

The 1830 Treaty of Prairie du Chien, negotiated between the United States and various tribes, established the Neutral Ground: the tribes agreed to land cession of a 40-mile-wide (64 km) strip of land, two strips of land 20 miles (32 km) wide each on either side of the boundary roughly from present-day La Crosse, Wisconsin and Prairie du Chien, Wisconsin, extending from the Mississippi River to the Des Moines River in what today is southeastern Minnesota and northeastern Iowa.

Fort Atkinson was founded to keep the Ho-Chunk on the Neutral Ground, and to protect them from other tribes as well as prevent white traders and settlers from intruding on Indian land.

The post was also reinforced the authority of the U.S. government official who operated a school, model farm and provided supplies to the Ho-Chunk.

After Co. B, 1st US Dragoons left in June 1846, to report to Ft. Leavenworth in response to the Mexican–American War, the post was briefly vacant.

Morgan's Company was reorganized as a mounted unit in July 1847 and helped moved the Ho-Chuck from Iowa to Minnesota in June 1848.