On June 18, 1805, Clark described Giant Springs as “the largest fountain or Spring I ever Saw, and doubt if it is not the largest in America Known, this water boils up from under th rocks near the edge of the river and falls imediately into the river 8 feet and keeps its Colour for ½ a mile which is emencely Clear and of a bluish Cast.” On June 29, Lewis and Drouillard hiked six miles from their upper portage camp to visit the spring after hearing Clark’s description. He found it “much as Capt. C; had discribed & think it may well be retained on the list of prodegies of this neighbourhood towards which, nature seems to have dealt with a liberal hand.”
Giant Springs is a first magnitude freshwater spring considered to be among the largest in the United States. It is the headwaters for the Roe River, which flows for only 200 feet before emptying into the Missouri. The nearby City of Great Falls was founded in 1883, and Giant Springs soon developed into a popular place for recreation. Giant Springs State Park, established during the 1970s, includes a trout hatchery. An extensive network of recreational trails along the Missouri River can be accessed from the park. The adjacent Lewis and Clark National Historic Trail Interpretive Center, managed by the USFS, provides interpretive opportunities to visitors.