Bookmark and Share

Rocky Mountain National Park Dayhiker's Guide describes 33 of the best day hikes in the park. Trails are cross-referenced with the RMNP Trails Illustrated topographic map.

Chasm Lake

Trail Features: Alpine Lake, Outstanding views, Fall Aspens chasm-lake
Trail Location: Longs Peak Ranger Station
Roundtrip Length: 8.4 Miles
Trailhead Elevation: 9405 Feet
Total Elevation Gain: 2450 Feet
Avg. Elev Gain / Mile: 583 Feet
Highest Elevation: 11,823 Feet
Trail Difficulty Rating: 13.30 (strenuous)
Parking Lot Latitude 40.27215
Parking Lot Longitude -105.55682

Trail Description:

The hike to Chasm Lake begins from the Longs Peak Trailhead. To reach the trailhead from Estes Park, drive 8.9 miles south from the intersection of U.S. 36 and Colorado Highway 7, to the turnoff for the Longs Peak Ranger Station. From the turnoff drive another mile to the ranger station. Please note that parking is fairly limited, and the lot fills up very early on weekends. Additional parking is available along the roadside leading up to the trailhead, but is also quite limited. You may also want to note that car-camping isn't allowed in the parking area.

Due to the popularity of the hikes from this trailhead, the length of time to reach most destinations, exposure to afternoon thunderstorms, and limited parking, you'll definitely want to arrive as early in the morning as possible, especially on weekends during the summer months. Day hikers planning to summit Longs Peak usually arrive between 3 a.m. and 5 a.m.

Starting at an elevation of roughly 9405 feet, hikers will be following the East Longs Peak Trail for most of this hike.

Longs Peak is the highest point in Rocky Mountain National Park. The 14,259-foot peak is named after Major Stephen H. Long, who led an expedition across the Great Plains and along the base of the Rockies in 1820. While out on the plains, in the distant view, the expedition could see the highest mountain in the northern range. Although they never entered Rocky Mountain National Park, three members of the expedition would later become the first to climb Pikes Peak.

John Wesley Powell, along with several others including William Byers, the founder of Rocky Mountain News, would make the first ascent of Longs Peak in 1868. Powell, the one-arm Civil War General, would also become the first person to float the Colorado River through the Grand Canyon.

longs-peak and mt-lady-washingtonFrom the Longs Peak Ranger Station the trail begins a steep climb through a thick forest of lodgepole pine, spruce and fir. Roughly one-half mile from the trailhead hikers will reach the Eugenia Mine Trail junction, and at 1.1 miles, will pass the short side trail that leads to the Goblins Forest Backcountry Campground (containing six individual campsites).

Two miles from the trailhead, at an elevation of roughly 10,600 feet, hikers will finally emerge from the forest and enter the subalpine zone. Dominating the landscape along this section of trail is krummholz, a German word that means twisted wood, which describes the stunted and irregular growth patterns of trees found in the transition zone between forest and tundra. Longs Peak and Mt. Lady Washington also come into view at this point as well.

longs-peak-diamondAt just under 2.5 miles you'll reach the spur trail that leads to the Battle Mountain Backcountry Campsite (contains one group campsite). Beyond the junction the main trail leaves the subalpine zone and begins to ascend Mills Moraine.

At roughly 3.5 miles, and at an elevation of 11,540 feet, hikers will arrive at the Chasm Lake Trail junction. From this point 13,281-foot Mt. Lady Washington will be the dominating feature towards the west. If needed, an outhouse is located here as well.

From the junction the Chasm Lake Trail travels southwest along the wall of a deep gorge that offers views of Peacock Pool and Columbine Falls. After a short rock scramble you'll arrive at the east end of Chasm Lake.

Chasm Lake sits in a deep cirque at the base of Mt. Lady Washington towards the north, and Longs Peak towards the west. The famous east-facing wall of Longs Peak, known as the "Diamond", rises more than 2,400 feet above this incredibly beautiful alpine lake. Looking towards the south is 13,911-foot Mt. Meeker. Much of the shoreline around the lake is accessible, but some minor scrambling is required to reach some of the better vantage points.


The national park website provides additional information on hiking in the Longs Peak area, as well as general hazards you should be aware of while hiking in the high country.

If you still have the energy, plenty of time, and good weather, you'll have the option of continuing on to the Boulder Field and the Keyhole.