Lake Lahontan (reservoir)

Infobox lake
lake_name = Lake Lahontan
image_lake =
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location = Northwest Nevada
coords = coord|39|24|06|N|119|06|49|W|region:US_type:waterbody|display=inline,title
type = reservoir
inflow = Carson River
outflow = Carson River
catchment =
basin_countries = United States
length = 17 mi (27 km)
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cities = Modern Lake Lahontan is a man-made reservoir on the Carson River in northwest Nevada in the United States. It is formed by the Lahontan Dam and is located between Fallon, Nevada and Carson City, Nevada. The flows from the Carson River is augmented by 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.

Lake Lahontan is 17 miles (27 km) long and has 69 miles (111 km) of shoreline. It consists of several lobes connected by narrow straits. When full, it has approximately 10,000 acres (40 km²) of surface area, although it is usually less than half full by late summer. As no water rights have been allocated for recreation, the TCID could completely drain the lake to supply its irrigation customers.

Recreational uses include fishing, pleasure boating and camping. As it is contaminated with mercury from the Comstock and other mines, consumption of fish from the lake should be limited as per posted guidelines. Much of the shoreline is sandy and makes for good camping.

The Carson River enters the lake at its southwestern end. The lake is very shallow there, and the shoreline can vary drastically as the lake empties and fills. The Truckee Canal enters at the northeastern end, immediately adjacent to the dam.