Low Point: 4789'
High Point: 7534'
DirectionsFrom Eugene, drive Highway 126 past McKenzie Bridge, turning right on Highway 242 (McKenzie Pass Highway). Follow this road as it winds up the Cascade Range until reaching a turnoff for Frog Campground and the Obsidian Trailhead (about a quarter mile from the highway).
After leaving the trailhead, the path climbs steadily through the mountain forest, passing a side trail that leads to Spring Lake at the 0.75-mile mark. The trail maintains its gentle grade for another mile before it steepens slightly. The footpath stays in the nice mountain forest, which without a lot of undergrowth feels moderately open, yet the impressive views that you know are coming still remain hidden. The path soon fully opens up when it arrives at a lava flow 2.6 miles from the trailhead. From here, you gain your first impressive views of the Middle and North Sisters, plus a panorama of foothills to the west.
Continue over the lava flow until reaching a fork in the trail. Turn left, towards Minnie Scott Spring, and follow this fork for approximately one mile until reaching a 5-way intersection. This intersection can be a little confusing, especially since I've determined that the USGS map for this area and trails is in badly need of updating. Take the left-most trail (the Pacific Crest Trail). This will lead you back towards a crossing of the large lava flow, 1.5 miles past the 5-way fork. Once the trail arrives at the lave flow, it climbs more steeply as it switchbacks its way up Opie Dilldock Pass and into the caldera of Collier Cone. The view from this section of trail is awesome, with all the mountains between Mt. Washington and Hood aligned along the horizon, while Little Brother and the North Sister loom overhead to the south. Follow the trail to the right, climbing up the ridge to Collier Glacier View. Make sure to bring a lunch and plan to spend a little while, as this makes for a good spot to sit and soak in your accomplishments! Impressive views of the Sisters, Collier Glacier, and most of the Oregon Cascade Mountains are presented in every direction. Very Impressive.