Round the Mountain Trail follows the rolling grades around the base of Mt. Adams. The general route has been used by Native Americans since at least the 1840s to access huckleberry patches on the north and west sides of the mountain. C.E. Rusk, his mother, and his 12-year-old sister were reportedly the first non-Native Americans to make a circuit of the mountain in 1890, using Native American trails that follow the same general route as the current trail.

Beginning from the Pacific Crest Trail near Horseshoe Meadows, the trail heads southeastward, at around 6000 feet elevation. The first trail junction is at 1.1 miles, with Looking Glass Lake Trail No. 9A. The trail continues for another 2.2 miles, crossing several glacier-fed meltwater streams, to the junction with Shorthorn Trail #16. The trail continues on for another 2.8 miles to the junction with the South Climb Trail No. 183. From here the trail follows the wilderness boundary, skirting the north end of the Aiken Lava Bed. The trail enters the Yakama Indian Reservation at the junction with Trail No. 11. The Forest Service maintains the trail to the reservation boundary. The section through Bird Creek Meadows is under management of the Yakama Indian Nation. Permits to use Yakama lands are available from rangers stationed at Bird Lake.

From here the trail enters Bird Creek Meadows on the Yakama Indian Reservation. The trail ends on Road 8290.285 in the reservation.

You can extend your trip by using a section of the Pacific Crest Trail from Horseshoe Meadows to the north. From here, head east and then south again on Highline Trail No. 114. In order to completely circle the mountain, you will need to negotiate a 4.5-mile section between Avalanche Valley and Bird Creek Meadows where there is no trail connection. This is difficult terrain to cross, with a number of extremely difficult stream crossings.

Round the Mountain Trail has numerous scenic opportunities, as it follows a generally rolling grade around the base of Mt. Adams. The slopes are splashed with color from wildflowers, amid the small subalpine fir and white bark pine. Other features include numerous crystal clear streams and up-close views of Mt. Adams. The trail also offers views of the massive debris avalanche that occurred in 1997, beginning in the Avalanche Glacier cirque, at the 12,000 feet elevation on the southwestern flank of Mt. Adams.

Permits are required to use the section of the trail in the Yakama Indian Reservation. (Overnight stay permits are available. Camping is allowed only in the designated sites.)