Fort Ridgely was a frontier United States Army outpost from 1851 to 1867, built 1853–1854 in Minnesota Territory.

Half of the fort's land was part of the south reservation in the Minnesota river valley for the Mdewakanton and Wahpekute tribes.

At Ridgely there were two Companies of troops that assisted in quarrying the granite two miles away, transporting it to the site, and the erection of a 400-man stone barracks.

In 1854–55, Congress approved $10,000 for the clearing of timber on a military road from St Anthony Falls to Fort Ridgely.

On July 22, 1856, Congress approved another $50,000 to build a wagon road from Fort Ridgely to South Pass, Nebraska Territory.

Marsh had requested assistance from C Company at Fort Ripley to oversee the annuity and provisions exchange at the Upper Sioux Agency.

Fort Ripley's executive officer, 1st Lt. Sheehan brought two Mountain Howitzers and 40 men to do the job.

Initially, Indian Agent Thomas Galbraith refused to extend credit to the Sissiton and Whapeton.

With that done and thinking their task was completed, C Company departed for their own post the morning that the lower Agency was overrun.

Unbeknownst to Sheehan, Galbraith had refused to extend credit to the Mdewakanton and Wahpekute at the Lower Sioux Agency.

B Company did not have the same military force presence at the Lower Sioux Agency and the situation there spiraled out of control.

[9] Some of the civilians were native Métis members of the Renville Rangers militia that had been in the process of departing for Fort Snelling to enlist in a Minnesota Volunteer Infantry unit.

He is credited with Ridgely's successful defense by organizing men with artillery experience to man three cannons, two 12-pounders and the 24-pounder.

[12] , Notable officers posted to Fort Ridgely included: In its time, numerous units were assigned to the outpost.

During the civil war Companies from Minnesota Volunteer Regiments served in place of the regular army.

On September 2, one hundred eighty miles west, the train ran into Sitting bull's warriors.

[19] In 1865-6 Captain Kellogg, Commander of Fort Ridgley, formed three settlements of friendly Sioux before the Lake Traverse Reservation was created.

Werner Boesch, the ex-Swiss artilleryman that had helped man a 12-pounder during the attacks, had a Fort Ridgely Defender Medal made for the occasion.

On it he quoted Big Eagle's comment about the Fort: "Ti-Yo-Pa Na-Ta-Ka-Pi" or they "Kept the Door Shut" to the lower Minnesota river valley.

The State erected another large monument to the Chief Mou-zoo-mau-nee and the Mille Lacs Band of Ojibwe in 1914.

The Minnesota Historical Society maintains the publicly owned portion within Fort Ridgely State Park.

[25] The old commissary building (partially reconstructed by the Civilian Conservation Corps in the 1930s) now houses the Park's museum.