Mount Tallac is a mountain peak southwest of Lake Tahoe, in El Dorado County, California. The peak lies within the Desolation Wilderness in the Eldorado National Forest. It is quite visible from State Routes 89 and 28, and U.S. Route 50. A "cross of snow" is clearly visible on the mountain's face during the winter, spring, and early summer months. The mountain is shown on maps of the Whitney Survey as Chrystal Peak.