Jumbo Mountain is an 8,284-foot summit in Powell County, Montana, in the Swan Range of the Rocky Mountains, within the Bob Marshall Wilderness on Flathead National Forest land. Its runoff feeds the headwaters of the South Fork Flathead River. The mountain is especially notable for its steep relief, with the west side rising about 3,400 feet above Youngs Creek in 1.5 miles and the south aspect climbing 2,000 feet above Jumbo Creek in half a mile. An active fire lookout built in 1957 stands on the summit, replacing a 1937 cabin. The area has a subarctic climate with long, very cold winters and short, cool to mild summers.