Iron Nation was one of the signers of the September 17, 1851, Treaty of Fort Laramie, along with people from Lakota, Cheyenne, Arapaho, and other tribes.

[3] Iron Nation also signed the October 14, 1865, Fort Sully Treaty with other Lakota chiefs, which established the Lower Brule Indian Reservation.

[4] Three years later, he signed the 1868 Treaty of Fort Laramie,[5] which eliminated U.S. forts along the Bozeman Trail in Montana and established the Great Sioux Reservation, permanently locating the Lower Brule tribe along the Missouri River in modern-day south-central South Dakota.

Iron Nation ultimately hoped this would allow his tribe to avoid involvement in the Sioux Wars, and he settled into a homestead on the reservation.

The inscription reads:[3] We, the Lower Brule Indians put up this stone in memory of our dear Head Chief Solomon Iron Nation Who died November 14, 1894, Aged 79 years.

[5] An 1867 photograph of Iron Nation by Alexander Gardner is held in the collections of the Princeton University Library.

[8] Two members of the Lower Brule Sioux Tribe produced a 12-minute animated film about Iron Nation in 1997.