Summer Lake is a large, shallow, alkali lake in Lake County, Oregon, United States located south of the small, unincorporated community of Summer Lake, Oregon. At high water it is about long and wide, and supports a wide variety of birds and other wildlife in its marshes. The lake was named by explorer John C. Fremont on his expedition into Central Oregon in 1843.

Summer Lake is an unincorporated community in northwest Lake County, Oregon, United States. It is on Oregon Route 31 approximately halfway between Bend and Lakeview. It is at the base of the eastern slope of Winter Ridge adjacent to the Fremont–Winema National Forests.