One of the iron posts used to mark the corner of the Fort Randall Military Reservation was originally located approximately two miles east and one-half mile north of Bonesteel. Permanent cast iron monuments six inches square and six feet tall marked "U.S. MIL. RES'N." were erected at the four corners of the reservation and at both sides of the Missouri River crossings above and below the fort, for a total of eight posts. Three other posts have been located in Pickstown, South Dakota, Gross, Nebraska, and Lynch, Nebraska.