Chasm Lake

Start hiking up the Longs Peak Trail from the trailhead. The trail is rocky and has steps created by trail crews the whole way. It is moderately steep as it switchbacks its way to a junction with Eugenia Mine Trail, roughly 0.5 miles in. Longs Peak Trail continues ascending above Alpine Brook, eventually crossing it at mile two. Shortly thereafter, you'll reach a junction with Jims Grove Trail and begin to emerge above tree line. Continue on Longs Peak Trail for another 0.8 miles to the Chasm Lake Trail. Turn right onto Chasm Lake Trail. This trail contours gently along the south face of Mills Moraine providing excellent views below of Peacock Pool and Columbine Falls along the Roaring Fork river. The gentle positive grades give way to equally gentle negative grades before the trail shows its second, and much more drastic character. After crossing the upper reaches of the Roaring Fork River, at roughly mile 3.7, this trail begins to climb very steeply and will require some scrambling up the outer side of the "wall" that holds the lake. This short but strenuous pitch is well worth it as you are quickly rewarded with the absurd views at Chasm Lake. From the lakeshore, you'll be able to view the majestic "Diamond," one of the steepest and most iconic rock faces in Colorado. Located on the east face of Longs Peak, The Diamond rises roughly 2400' straight up. There are privies located approximately at the intersection of Chasm Lake Trail and Longs Peak - Keyhole Route and also just below Chasm Lake next to a Ranger station (small rock building) in the marshy area.

Chasm Lake sits in a semi-circular, steep sided scar, known as a cirque, that is indicative of the top of a glaciated valley. A moraine (as in Mills Moraine) is a field of debris left behind by a glacier as it melts that it scraped and tore from the walls of the valley it moved down.