The University of California, Davis (also referred to as UCD, UC Davis, or Davis) is a public teaching and research university located in Davis, California just west of Sacramento. The campus covers 7,309 acres (2,958 ha), making it the largest within the 10 campus University of California system. UC Davis also has the third largest enrollment in the UC System after UCLA and UC Berkeley. The University of California, Davis campus is the largest campus in the UC system by land area, spanning 7,309 acres (2,957.8 ha) across two counties: Yolo and Solano. Though named after the City of Davis, the campus is technically located adjacent to the City of Davis in an unincorporated part of Yolo and Solano counties. The main campus is located 15 miles (24.1 km) west of Sacramento in the Sacramento Valley, part of California's Central Valley, and is adjacent to Interstate Highway 80. The Davis campus is the only school within the UC system with an airport, just west of main campus, and is one of two UC schools with its own fire department; the other being UC Santa Cruz. The campus is also conveniently located approximately an hour away from both San Francisco and the Napa Valley and two hours from Lake Tahoe. It is also one of only three schools in the University of California system, the others being UC Berkeley and UC Irvine, with a nuclear lab.