Fourth Lake via East Inlet Trail

Fourth Lake via East Inlet is a hard, high-elevation out-and-back to the upper East Inlet basin. Plan on about 16.8 miles round trip and roughly 10 to 12 hours. The mapped corridor is about 8.4 miles each way to the shore of Fourth Lake; the route stops there, before the continuation toward Fifth Lake. Published mileage conflicts: one figure is 8.2 miles with an unclear out-and-back convention, while the mapped route and a 2025 on-foot measurement put Fourth Lake about 8.3 miles one way. I use the full round-trip distance.

The trail begins at East Inlet Trailhead near Grand Lake. Seasonal timed-entry rules can apply to this outlying park area, even though the starting access is on the west side; check current Rocky Mountain National Park entry requirements before going. Dogs are prohibited on park trails and meadows.

The first stretch winds through pine and aspen and passes the short Adams Falls walk. The falls drop in steps through a narrow rock gorge, and most visitors turn back here. Keep going and the route settles beside East Inlet Creek before opening onto East Meadow, where the creek runs beneath Mount Cairns, Mount Craig and Mount Wescott. A low bluff above the meadow is a good place to look for elk, moose or deer.

Beyond the open valley, the trail climbs the rocky lower slopes of Mount Cairns. The route is well built in places, with stone staircases on the steeper pitches, but it also contours beneath cliffs and gains height in stages. Look back for views toward Grand Lake and the Kawuneeche Valley. This is a long day at high altitude, and snow or ice can linger on higher stretches into summer.

Lone Pine Lake is the first major lake stop, about 5.3 miles from the trailhead. A granite slab near its southwest shore gives you a seat and a clear view of the small granite island and the peaks across the water. Lake Verna comes later, after another climb over a saddle; the trail follows its forested shore and opens to broader views near the northeast end. Lake Verna is a sensible turnaround if the full distance or the rougher upper trail is more than you want.

The path past Lake Verna is less improved and can be faint in places. It climbs toward Spirit Lake, then continues through the upper lake basin to Third Lake and Fourth Lake. Expect a quieter, rougher finish than the popular lower East Inlet trail. Follow the line carefully and treat Fourth Lake as the end of this hike; the continuation toward Fifth Lake is a separate extension.

The East Inlet route is an example of naturalistic trail construction by the National Park Service and Civilian Conservation Corps, using local rock, wood and dirt. Its stone steps and drainage work are part of that design, and the trail was added to the National Register of Historic Places in 2005. Adams Falls takes its name from Jay E. Adams, an early Grand Lake settler, rather than the Colorado senator.