The northern half of the county is the Modoc Plateau, a high expanse of lava flows, cinder cones, juniper flats, pine forests, and seasonal lakes, plus the alkaline Goose Lake. Nearly 1 million acres (4,000 km2) of the Modoc National Forest lie on the plateau between the Medicine Lake Highlands in the west and the Warner Mountains in the east. The plateau supports large herds of mule deer (Odocoileus hemionus), Rocky Mountain Elk (Cervus canadensis), and pronghorn (Antilocapra americana). There are also several herds of wild horses on the plateau. The Clear Lake National Wildlife Refuge and Long Bell State Game Refuge are located on the plateau as well. The Lost River watershed, which later drains into the Klamath River basin, drains the north part of the plateau, while southern watersheds either collect in basin reservoirs or flow into the large Big Sage Reservoir, which sits in the center of the county, which later flows into the Pit River.