Cathedral Lake is a lake inside of Maroon Bells–Snowmass Wilderness Area. Parking for this hike is on Castle Creek Rd in Aspen. Drive past the historic town of Ashcroft and be on the lookout on your right to the small road that will take you to the trailhead. It is marked for Cathedral Lake.This hike is difficult as it gains almost 1,900 feet in elevation until it reaches the lake in less that 3 miles. There is not much shade after one crosses the first part of the aspens so please make sure you have plenty of water, sunscreen, a hat and watch for signs of dehydration and sun exposure. From the TH follow the trail as it steeply and relentlessly gains altitude. You will cross a few avalanche paths that have been cleared out for hikers to go through as well as a rocky path. As you ascend, you will also go through a series of steep switchbacks that will eventually level out. Once you past the switchbacks you will see a split on the trail and sign for "Electric Pass" to your right but you need to continue towards Cathedral Lake so please disregard it. Soon after, the trail descends and meets the creek. Find a safe place to cross it as there is not bridge. If water is running very high or swiftly, please be careful as run out in the summer can be very dangerous. You will see that the trail continues past the crossing of the creek for less than a 1/4 mile until it reaches the lake. Please remember this is wilderness. Follow Leave No Trace and have dogs on a leash.