This park encompasses 977 acres at the confluence of the Heart and Missouri Rivers. Originally called Fort McKeen, the fort's present name was adopted in 1872. It includes the site of Fort Abraham Lincoln, from which Lt. Col. George Custer led 265 men to annihilation in the 1876 Battle of the Little Bighorn against the Sioux Nation.

This locality was the site of several significant historical events. The North West Co. established a fur-trading expedition post on the site in 1780; Lewis and Clark explored the area 1804-06; and Custer and his 7th Cavalry arrived in 1873.

Park open daily 8am-dusk.