Twin Sisters is a moderately difficult hike that provides exceptional views of Rocky Mountain National Park and the surrounding areas.
The trailhead begins at an elevation of approximately 9,225 feet and gradually ascends through the lodgepole pine forest. The first mile of this trail is moderately easy as it exits Rocky Mountain National Park and enters into Roosevelt National Forest. Keep an eye out for elk, as the herds like to linger in the woods during the day.
Hikers will reach a major landslide area approximately a quarter-mile further along the trail. This large landslide occurred in September, 2013, when the area received heavy precipitation in just a few short days. The landslide has washed out portions of the first three switchbacks on the trail. The trail has evolved by crossing over to the south side of the washout. At this point the trail quickly ascends up a series of scrambling switchbacks. The trail becomes slightly less defined in this area as several spurs leave the main trail, but navigating this area is relatively straightforward.
After about a quarter-mile of additional strenuous climbing, the trail gradually eases up and enters into the higher limber pine forests. Views of Longs Peak, Mount Meeker, and the continental divide begin to emerge toward the west. At 3 miles a series of gradual switchbacks continues to climb out of the forest and onto a saddle. From here you can see the front range and surrounding foothills toward the east. The trail crosses a large talus field at 11,000 feet, but this section is easy to navigate toward the summit.
At 3.5 miles a quick scramble up the last 500 feet of the talus field puts you on top of the 11,428-foot East Twin Sisters Peak. You'll have expansive views of the entire Rocky Mountain National Park and surrounding Indian Peaks Wilderness. There is also an optional scramble to the 11,413-foot West Twin Sisters Peak. This hike is approximately 7 miles there-and-back and gains 2,203 feet of elevation. The entire hike takes about 3 to 3.5 hours depending on how briskly you hike up.