The Klamath Basin National Wildlife Refuge Complex is a wildlife preserve operated by the United States Fish and Wildlife Service in the Klamath Basin of southern Oregon and northern California near Klamath Falls, Oregon. It consists of Bear Valley, Klamath Marsh and Upper Klamath National Wildlife Refuge (NWR) in southern Oregon and Lower Klamath, Tule Lake, and Clear Lake NWR in northern California. Upper Klamath NWR, established in 1928, is composed of 15,000 acres (61 km2) of mostly freshwater marsh and open water.