Pyramid Lake is the biggest remnant of the prehistoric Lake Lahontan, located 40 miles northeast of Reno in western Nevada. Named for a prominent rock formation and fed by the Truckee River, Pyramid Lake was utilized by the Paiute for fishing, while the Shoshone and Washo also regularly fished in the lake. John C. Fremont was the first non-Native American to map the lake. The Paiute War of 1860 saw two battles be fought near the lake. In 1905, the lake's existence was threatened by the constructin of the Derby Dam, leading to the Paiute suing the Department of the Interior. The water diversion led to the near-exstinction of the Lahontan cutthroat trout.