Giant Springs Trail

The Giant Springs Trail loops around one of the largest freshwater springs in the world, a geological phenomenon where ancient aquifer water emerges from the base of a limestone bluff at the edge of the Missouri River, discharging an estimated 156 to 388 million gallons of crystal-clear water daily at a constant temperature of 54 degrees Fahrenheit. The spring pool is an arresting sight: impossibly clear water wells up continuously from sandy vents in the pool floor, its volume enormous enough to sustain a substantial watercourse all its own.

Lewis and Clark encountered and described Giant Springs during their 1805 portage around the Great Falls of the Missouri River, and Meriwether Lewis wrote enthusiastically about the spring clarity and volume in his expedition journals. The short Roe River exits Giant Springs and flows just 200 feet before entering the Missouri, earning recognition in the Guinness World Records as the world shortest river. The trail passes an interpretive area explaining the hydrological system that feeds the springs, tracing groundwater movement from the Little Belt Mountains through an extensive limestone aquifer over a journey estimated to take several thousand years. Rainbow trout are visible in the crystal-clear spring outflow pool, and the constant water temperature supports year-round biological activity in an otherwise seasonally frigid Montana climate.