DirectionsFrom Portland, take Interstate 5 to Woodland Exit 21 (north of Portland 25 miles) and turn right (503) for 28 miles, following signs for Cougar. Just before you reach the town of Cougar turn left on Road 8100 (there will be a sign for Merrill Lake). Take this paved road 11.5 miles and then continue straight on gravel Road 8123 (8100 turns to the right here) for 1.5 miles to the Blue Lake Trailhead. Parking permit is required.
This 11-mile loop has an elevation gain of 1900 feet and is open late June through October. Situated on the SW side of Mt St. Helens this hike takes you along Sheep Canyon, the South Fork Toutle River’s mudflow canyon, and the edge of the 1980 eruption’s blast zone. The scenery is great on this hike, with many different landscape changes along the way including great views of the mountain at different angles as you travel the loop. I highly recommend this hike! A more detailed description of this hike can be found in William L. Sullivan’s; “100 Hikes in Northwest Oregon” (second edition).