Lake Vernon is located in the Tiltill Valley in the northern sector of Yosemite National Park north of Hetch Hetchy Valley . Lake Vernon is located in the Tiltill Valley in the northern sector of Yosemite National Park just north of Hetch Hetchy Valley . Lake Vernon is located in Tiltill Valley , in the northern part of the Hetch Hetchy Valley north of Yosemite National Park .