Fort Ripley was a U.S. Army outpost on the upper Mississippi in what is now central Minnesota, active from 1848 to 1877 in a strategically important travel and trade corridor. Established to oversee the nearby Ho-Chunk reservation, manage annuity payments, and help separate the Santee Dakota and Ojibwe, it also encouraged immigration and the growth of nearby Crow Wing. During the Civil War era and the U.S.-Dakota War of 1862, it became a stronger defensive post, aided by militia and Ojibwe allies including the Mille Lacs Band. After nearly three decades on the northern frontier, it closed in 1877 and later became an archaeological site within Camp Ripley.