The Smith River originates in the Castle Mountains (8500') of central Montana and flows north between the Little Belt (to the east) and Big Belt (to the west) ranges, both about 9000' in elevation. The river gathers more water from half a dozen tributaries and finally empties into the Missouri River about 10 miles upstream of Great Falls. The 60-mile float trip begins north of White Sulphur Springs at Camp Baker. The next public access site is five days away at the Eden Bridge take-out.