East of Durango and northeast of Pagosa Springs in the Weminuche Wilderness Area, the Rainbow Trail leads to scenic hot springs pool. There are two man-made, sandy-bottom pools in the rock beside the river perfect for soaking in. While this strenuous 4 mile ride in through scenic wilderness, it is very popular and can be quite crowded on the weekends. Matter of fact, expect plenty of campers near the springs.
To reach the horseback riding trailhead from Pagosa Springs, head northeast on US160 for about 16 miles. Watch for sign to West Fork Campground on the left (west) side. Turn left heading west on CR648 towards West Fork Campground and Borns Lake for 6.9 miles to the trailhead parking.
Start hiking up the trail past the Borns Lake community. This is a 4 mile one-way hike with about 1,000 feet of vertical. It is a difficult route combining old forest roads and very narrow ledge trails with a loose scree tread. The last mile can be the most difficult.
Keep in mind that the springs are not marked. Watch for the remanants of the fire rings about a half mile or so past the fork in the trail.
While most of the river crossing are bridged now, the hot springs are submerged during the spring run-off.
Overall, Rainbow Hot Springs is the 12th most popular horse trail of all 67 horseback rides in Colorado.