This very short .3 mile spur trail off the Union Falls Trail
leads to a naturally heated swimming hole at the base of a small falls, known as "Scout Pool."
The North Fork Trail leaves the Union Falls Trail
1.6 miles from its start (.5 miles before reaching Union Falls
). The North Fork Trail branches to the left and follows Mountain Ash Creeks large unnamed tributary (sometimes called the "North Fork"). The easy, level trail ends at the base of a small, 8-foot waterfall. The water of this creek emanates from myriad hot springs flowing out from the base of the Pitchstone Plateau, making it warm enough to swim. Just below the falls are several nice soaking spots.
Thanks to guidebook author, Tom Carter, for sharing this trail description. To learn more about visiting Yellowstone, check out his book, Day Hiking Yellowstone