Modern Lake Lahontan is a reservoir on the Carson River in northwest Nevada in the United States. It is formed by the Lahontan Dam, built in 1905 by the Bureau of Reclamation as part of the Newlands Reclamation Act and is located between Fallon, Nevada and Carson City, Nevada. The flows from the Carson River is augmented by the diversions from the Truckee River. The reservoir is maintained by the Truckee-Carson Irrigation District (TCID).The lake is named after ancient Lake Lahontan, which covered much of northwestern Nevada during the last ice age.