The Threemile Trailhead provides access to the Threemile Creek Trail, which connects with the Rosalie Trail in the Mount Evans Wilderness. The first part of the trail follows Threemile Creek in a northeasterly direction. The stream and trail are in a narrow canyon with a number of stream crossings. As the trail swings more toward the east, it gradually begins to open up into a meadow. From a point east of Spearhead Mountain, the trail begins to rise steeply away from the creek in a series of switchbacks. As you ascend these switchbacks, look behind you from time to time for dramatic views to the southwest of Kenosha Pass, South Park, and the mountains west and south of Fairplay. At the top of the switchbacks the trail begins heading north. You will still be in trees and gaining elevation, but at a much lower rate than the steep switchbacks. Shortly, you will emerge from the trees into open tundra. Kataka Mountain will be on your left (west) and Mt Evans and Mt Bierstadt will be ahead of you and slightly to the left (north/northwest). Continuing north, the trail descends to meet the Rosalie Trail.
Drive southwest from Denver on US 285 approximately 40 miles to Grant. Turn right (north) onto Park County 62 (towards Guanella Pass), and drive 2.8 miles to the trailhead on the right (east) side of the road. There is a limited amount of parking at the trailhead.