www.tucsonaz.gov 1 Urban = 2000 Census Tucson ( /ˈtuːsɒn/ TOO-son) is the county seat of Pima County, Arizona, United States, and is the home of the state's first university, The University of Arizona. The 2010 United States Census puts the city's population at 520,116, while the entire Tucson metropolitan area's population is 1,020,200. Tucson is the second-largest populated city in Arizona behind Phoenix, which both anchor the Arizona Sun Corridor. The city is located 118 miles (188 km) southeast of Phoenix and 60 miles (98 km) north of the U.S.-Mexico border. Tucson is the 32nd largest city and 52nd largest metropolitan area in the United States. Roughly 150 Tucson companies are involved in the design and manufacture of optics and optoelectronics systems, earning Tucson the nickname Optics Valley. Major incorporated suburbs of Tucson include Oro Valley and Marana northwest of the city, Sahuarita south of the city, and South Tucson in an enclave south of downtown. Communities in the vicinity of Tucson (some within or overlapping the city limits) include Casas Adobes, Catalina Foothills, Flowing Wells, Tanque Verde, Tortilita, New Pascua, Sahuarita and Vail. Towns outside the Tucson metro area include Benson to the southeast, Catalina and Oracle to the north, and Green Valley to the south. The English name Tucson derives from the Spanish name of the city, Tucsón , which was borrowed from the O'odham name Cuk Ṣon , meaning "(at the) base of the black ", a reference to an adjacent volcanic mountain. Tucson is sometimes referred to as "The Old Pueblo."