Fort Ransom was a United States military post established on this site on June 18, 1867, as one of a chain of forts in Dakota Territory created to protect frontier settlements. Its buildings were of substantial log construction and provided quarters for 200 enlisted men and 7 officers. The post was defended by two block houses, a breastwork of log and sod construction, and a dry moat 8 feet deep. After Fort Seward was established at Jamestown in 1872, when the Northern Pacific Railway reached that point, Fort Ransom was no longer needed and was abandoned by the government on May 27, 1872.