There are hot springs, known as the Belknap Hot Springs, on the northern bank of the McKenzie River. Located in Lane County, they were discovered by R. S. Belknap in November of 1869. They lie to the southwest of the wilderness area, ejecting water at a rate of per minute with a temperature of . The hot springs are indicative of a fault that underlies the Cascade Volcanoes, onto which the east side dropped down and lava intrusions formed volcanic centers.