Pyramid Lake in Northern Nevada, near Reno. The Virginia Mountains are in the background. It lies on the Pyramid Piute Indian Reservation, and remains undeveloped as a sacred place. Pyramid Lake is an endorheic salt lake, approximately 188 square miles in area, in the Great Basin. One of the largest lakes in the United States. It lies on the east side of the Virginia Mountains. The lake is the largest remnant of ancient Lake Lahontan that covered much of northwestern Nevada at the end of the last ice age.