Flat Top Mountain Trail is a hiking trail in Larimer County, Colorado. It is within Rocky Mountain National Park. It is 3.7 miles long and begins at 9,971 feet altitude. Traveling the entire trail is 7.6 miles with a total elevation gain of 2,752 feet. Along the trail there are a spring and a scree. The trail ends near the Flattop Mountain (elevation 12,326 feet) saddle. There are also information guideposts near the end of the trail.