The Grebe Lake trail begins on the Norris-Canyon Road, near Canyon Village in the central region of the park. To reach the trailhead drive west from Canyon Village Junction for ±3 miles, and park in the drive-through parking area on the north side of the road. If approaching from the west the trailhead is located ±9 miles from Norris Junction.
If Observation Peak is being climbed as part of an overnight backpacking trip, there are 4 backcountry campsites well-situated near Grebe Lake:
4G2 - A very nice site right along the south shore of the lake
4G3 - Located near the northwest corner of the lake.
4G4 - Located on the north shore of the lake, roughly midway between 4G3 and 4G5.
4G5 - Located near the northeast shore of the lake.
Refer to the main page "Red Tape" section for additional details and information on backcountry camping in Yellowstone.
One-Way Hiking Distance: 7.5 miles
Elevation Gain: 1,277 feet
Trailhead Elevation: 8,120 ft.
Summit Elevation: 9,397 ft.
Average Gain per Mile: 170 ft.
From the trailhead parking area the Grebe Lake Trail heads northeast, paralleling a small creek for the first 3/4 mile. This first part of the trail follows the vague outline of an old fire road.
The trail then makes a turn northward and leaves the stream. The remaining two miles of trail to the lake passes through the remains of forested area which were completely burned in the 1988 fires which ravaged Yellowstone.
After 3.1 miles the trail arrives at the southeast shore of Grebe Lake. For those camping at Grebe Lake, campsite 4G2 is located a short distance to the west on the south shore of the lake.
Follow the trail through a marshy area along the southeast shore of the lake to a trail junction. The left fork heads west along the north shore of the lake, and provides access to campsites 4G3, 4G4, and 4G5; take the right fork which heads east.
Follow the trail for 1.9 miles, passing through several more marshy areas, until arriving at the southwest corner of Cascade Lake. The trail then follows the west shore of Cascade lake. Contiue past the lake a short distance to a signed fork in the trail, and take the left (west) fork.
From this point the trail begins climbing at a moderate but steady grade for the next 3 miles to the summit of Observation Peak. In early summer the hillsides along the way will be covered with wildflowers. There are also great views looking back at Cascade Lake.
The trail levels out somewhat before reaching the summit. On the summit is an old fire lookout structure, which is apparently no longer in use.
The Grebe Lake area is notorious for its mosquito population. Carry insect repellent for any summer hike before mid-August.
The trail passes through a meadow along the east shore of Grebe Lake, which may be marshy well into the summer - wear shoes that you don't mind getting wet and muddy.