Flattop Mountain is a 3,510-foot (1,070 m) mountain in the U.S. stateof Alaska, located in Chugach State Park just east of Anchorage. It is the most climbed mountain in the state.

It is usually reached by driving to the Glen Alps trailhead and following a well-maintained 1.5-mile (2.4-km) trail, with an elevation gain of 1280 feet (390 m) from the parking lot to the summit. Since it is the most accessible mountain to Anchorage, Flattop is a very popular location for hiking, climbing, berry picking, parasailing, and backcountry skiing. Campouts are held on the summit at the summer and winter solstices.

Flattop is known for its panoramic views of Anchorage and the surrounding area, including Denali, Mount Foraker, and Mount Spurr.