The Alkali Lakes are a series of three large playas located in the Surprise Valley of northeastern California, United States. From north to south they are known as Upper, Middle and Lower Alkali Lake. Upper Alkali Lake is often known simply as Upper Lake, and Lower Alkali Lake as Lower Lake. Although mostly located in Modoc County, California, the eastern edges of Middle and Lower Lakes touch Washoe County, Nevada. The Warner Mountains are located to the west of the three lakes. The lake beds are typically flooded with shallow water in the winter but dry up during most summers.