Part of the Great Basin region of the United States, Lake County is home to numerous large alkali lakes. Summer Lake is a large, shallow, alkali lake in Lake County, Oregon, United States. At high water it is about 15 miles (24 km) long and 5 miles (8 km) wide, and is located 5 miles (8 km) south of the small, unincorporated community of Summer Lake, Oregon. The lake was named by explorer John C. Fremont on his expedition into Central Oregon in 1843. The marshes around the lake support a wide variety of birds and other wildlife.

The Summer Lake Basin supports more than 250 species of birds including bald eagles, Canada geese, white faced ibis, yellow-headed blackbirds, goshawks, hermit thrushes, red-tail hawks, great blue herons, and numerous species of ducks. This makes Summer Lake a favorite bird watching and hunting area.

Best time to visit: March – April for viewing migrating flocks of waterfowl including plumaged ducks, geese and swans.
April – May for viewing migrant waterbirds and songbirds passing through the area.

At the south end of Summer Lake lies ancient artesian hot mineral springs.