Enter Rocky Mountain National Park from Estes Park. Use the Fall River entrance and follow the road for 2.3 miles and take a right onto Fall River road which starts as pavement and quickly becomes well maintained dirt. Follow Fall River road for about 9 miles to some pull-outs at the Chapin Pass trailhead. Parking is limited so get there early.
From the Chapin Pass TH follow the trail for about 200 yards until you see a sign and trail to the right that list Ypsilon Mountain. Take this trail as it leads up a crest to a fork just below treeline. If you are only interested in Mount Ypsilon then take the left branch. This trail leads north and finally peters into tundra just below the Chapin/Chiquita saddle. There is no true trail from this point on. Once you get to the saddle you can either ascend to Mount Chiquita's 13,069 summit (recommended) or make a rising traverse that contours North around Chiquita just below the summit to the Chiquita/Ypsilon saddle. From the saddle take the path of least resistance northeast to the summit of Ypsilon. This is about 3.5 miles from the trailhead.
No special gear for the summer season. Winter will require axe and crampons. A set of skis could make for a rapid descent back to the trailhead.
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