Santa Barbara County has a mountainous interior abutting several coastal plains on the west and south coasts of the county. The largest concentration of population is on the southern coastal plain, referred to as the south coast - meaning the part of the county south of the Santa Ynez Mountains. This region includes the cities of Santa Barbara, Goleta, and Carpinteria, as well as the unincorporated areas of Hope Ranch, Summerland, Mission Canyon, Montecito and Isla Vista, along with stretches of unincorporated area such as Noleta. North of the Santa Ynez range in the Santa Ynez Valley are the towns of Santa Ynez, Solvang, Buellton, Lompoc; the unincorporated towns of Los Olivos and Ballard; the unincorporated areas of Mission Hills and Vandenberg Village; and Vandenberg Air Force Base, where the Santa Ynez River flows out to the sea. North of the Santa Ynez Valley are the cities of Santa Maria and Guadalupe, and the unincorporated towns of Orcutt, Los Alamos, Casmalia, Garey, and Sisquoc. In the extreme northeastern portion of the county are the small cities of New Cuyama, Cuyama, and Ventucopa. As of January 1, 2006, Santa Maria has become the largest city in Santa Barbara County.