Tiltill Valley is a remote valley in northern Yosemite National Park

Yosemite National Park

Yosemite National Park is a United States National Park spanning eastern portions of Tuolumne, Mariposa and Madera counties in east central California, United States. The park covers an area of and reaches across the western slopes of the Sierra Nevada mountain chain...

. It is accessible only to hikers and equestrians. The valley is most easily reached via trail heads in the vicinity of the Hetch Hetchy Valley

Hetch Hetchy Valley

Hetch Hetchy Valley is a glacial valley in Yosemite National Park in California. It is currently completely flooded by O'Shaughnessy Dam, forming the Hetch Hetchy Reservoir. The Tuolumne River fills the reservoir. Upstream from the valley lies the Grand Canyon of the Tuolumne. The reservoir...

 and Lake Eleanor

Lake Eleanor

Lake Eleanor is a reservoir located in Yosemite National Park at an altitude of . The reservoir has a capacity of and a surface area of 953 acres...

. The valley provides access to many remote alpine lakes throughout the largely untamed wilderness that defines the northern portion of Yosemite National Park and the adjacent Emigrant Wilderness

Emigrant Wilderness

The Emigrant Wilderness of Stanislaus National Forest is a wilderness area in the Sierra Nevada mountains of California, USA. It is bordered by Yosemite National Park on the south, the Toiyabe National Forest on the east, and State Route 108 on the north. It is an elongated area that extends...

.