The South Boundary Trail east from Yellowstone's South Entrance travels 37 miles to the upper Yellowstone River, near the Thorofare Patrol Cabin. The trail is divided into three sections. The first is this 12.6-mile section from the South Entrance to Harebell Patrol Cabin.
The trailhead for the South Boundary Trail: South Entrance-Harebell lies just north of the South Entrance Gate at the Snake River Picnic Area. It begins with a big, potentially dangerous, ford. The Snake River here is braided and must be crossed in several sections. The last section is the main channel and it can be very deep. It usually is unfordable until August, and even then can be waist-deep. Visitors intent on taking the South Boundary Trail before the Snake subsides can begin their journey 3 miles south of the park off the Shelfield Creek Road, on the left just past the highway crossing of the Snake. An unmarked route leads north from there along the Snake and picks up the South Boundary Trail on the east side of the river.
The Snake's name comes from sign language used to describe the Snake or Shoshone Indians. They were excellent basket weavers and the sign for their name was a serpentine movement of the hand as if weaving.
Once past the ford, the trail bends left and travels through thermally affected areas. Not far away, the Lewis River flows into the Snake. The trail parallels the Snake River but stays mostly in the trees for the first 5.1 miles. It then breaks out and makes a bridged crossing of a large, very hot thermal runoff channel. Its source is Snake Hot Springs, just ahead to the right of the trail. The scenery is quite nice as the trail nears the Snake. There are several campsites in the area.
At the 6-mile mark the trail passes a junction with the Heart Lake Trail
, begins a big bend to the right, and rolls up and down through a large forest fire burned area. At 8.8 miles, the trail passes the Snake River Cutoff Trail
and enters a nice mile-long meadow. At 10.1 miles, the trail drops to a knee-high crossing of Coulter Creek just south of its confluence with the Snake. From here, the trail climbs over 500 feet through the trees in the next 1.5 miles and continues over rolling terrain the last mile to the Harebell Patrol Cabin on Harebell Creek.
Thanks to guidebook author, Tom Carter, for sharing this trail description. To learn more about visiting Yellowstone, check out his book, Day Hiking Yellowstone