According to the U.S. Census Bureau, the county has a total area of 3,789 square miles (9,810 km²), of which 2,735 square miles (7,080 km²) is land and 1,054 square miles (2,730 km²) (27.8%) is water.
Four of the Channel Islands – San Miguel Island, Santa Cruz Island, Santa Rosa Island and Santa Barbara Island – are in Santa Barbara County.
They form the largest part of the Channel Islands National Park (which also includes Anacapa Island in Ventura County).

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.

The principal mountain ranges of the county are the Santa Ynez Mountains in the south, and the San Rafael Mountains and Sierra Madre Mountains in the interior and northeast.
Most of the mountainous area is within the Los Padres National Forest, and includes two wilderness areas: the San Rafael Wilderness and the Dick Smith Wilderness.
The highest elevation in the county is 6820 feet (2079 m) at Big Pine Mountain in the San Rafaels.

North of the mountains is the arid and sparsely populated Cuyama Valley, portions of which are in San Luis Obispo and Ventura Counties.
Oil production, ranching, and agriculture dominate the land use in the privately owned parts of the Cuyama Valley; the Los Padres National Forest is adjacent to the south, and regions to the north and northeast are owned by the Bureau of Land Management and the Nature Conservancy.
According to the U.S. Census Bureau, the county has a total area of 3,789 square miles (9,810 km²), of which 2,735 square miles (7,080 km²) is land and 1,054 square miles (2,730 km²) (27.8%) is water. Four of the Channel Islands – San Miguel Island, Santa Cruz Island, Santa Rosa Island and Santa Barbara Island – are in Santa Barbara County. They form the largest part of the Channel Islands National Park (which also includes Anacapa Island in Ventura County).
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.
The principal mountain ranges of the county are the Santa Ynez Mountains in the south, and the San Rafael Mountains and Sierra Madre Mountains in the interior and northeast. Most of the mountainous area is within the Los Padres National Forest, and includes two wilderness areas: the San Rafael Wilderness and the Dick Smith Wilderness. The highest elevation in the county is 6820 feet (2079 m) at Big Pine Mountain in the San Rafaels.
North of the mountains is the arid and sparsely populated Cuyama Valley, portions of which are in San Luis Obispo and Ventura Counties. Oil production, ranching, and agriculture dominate the land use in the privately owned parts of the Cuyama Valley; the Los Padres National Forest is adjacent to the south, and regions to the north and northeast are owned by the Bureau of Land Management and the Nature Conservancy.
Santa Barbara County, California