Chapin Pass trailhead is located on Old Fall River Road inside the Fall River Road Entrance of Rocky Mountain National Park. From Estes Park take Highway 34 to the Fall River Entrance. From the entrance follow the road just past the viewing area for bighorn sheep, with Bighorn Mountain on your right. Turn right after 2 miles in the park and head up Old Fall River Road. Travel 6.9 miles up Old Fall River Road, counting from when it turns to dirt. The trailhead has a clear sign. Park on the turn out at the left side of the road. Note that Rocky Mountain National Park has a substantial entry fee and pet restrictions.

From the Chapin Pass trailhead ( 2) at 11,000 feet, head uphill just a few hundred yards to a right turn marked with a sign for "Chapin, Chiquita & Ypsilon Summits" ( 3). Follow the clear trail over a small drainage and gradually uphill ( 4), ( 5).

At 0.75 miles, reach a trail split with a sign pointing right to "All Summits" ( 6). Go right. Reach another trail split shortly thereafter without a sign ( 7). Go right again.

At around 1.25 miles from the trailhead, the route skirting Mt. Chapin (12,454') and ascending Mt. Chiquita (13069') comes into view ( 8). The true summit of Mt. Chapin is the more eastern (closest to Chiquita) of the high points visible from the trail. There is no formal trail to the summit of Mt. Chapin - pick an ascent point and gain 400 feet of class 2 tundra to reach it. Return to the trail to continue to the Chapin-Chiquita saddle.

On the approach to the Chapin-Chiquita saddle at 12,000 feet, cross a trail intersection and keep going straight ( 9). Continue up on clear trail until it dissolves into class 2 rock ( 10) at around 2.5 miles and 13,000 feet. Cross the rocks to the true summit ( 11).

From Chiquita's summit, survey Ypsilon ( 1) and the route across the saddle ( 12). Head west off the Chiquita summit to access the saddle, which drops just 200 feet ( 13). Ascend across tundra on the other side of the saddle ( 14), more or less passing just inside of Ypsilon's east face. Follow cairns once it turns to Class 2 rock ( 15), climb toward the first false summit at around 13,300 ( 16), find more cairns and distinct vertical flakes of rock ( 17), and approach another false summit ( 18) just after the southern branch of the Ypsilon "Y" couloir for which the mountain was named. Pass this and find the true summit (13,514') at 4 miles from the trailhead, just beyond the northern branch of the "Y" ( 19).

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