The Soda Lakes are two lakes located northwest of Fallon, Nevada. They occupy two basaltic maar volcano craters which may have erupted in the last 1500 years. The larger lake, called Soda Lake or Big Soda Lake, is somewhat elongated, stretching 2 kilometers (1.2 mi) in length. The smaller one, Little Soda Lake, is 200 meters (660 ft) across. Considered to be a single volcano, the combined craters are young enough that future activity can't be ruled out. A geothermal power plant is located on the northeast flank of the volcano.

A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption. A maar characteristically fills with water to form a relatively shallow crater lake, which may also be called a maar.