Tar from natural oil seeps in the Summerland area was long used as a sealant, both by the native Chumash peoples and by the Spanish builders of the Mission Santa Barbara, who used it as waterproofing for the roof. In 1883, spiritualist and real estate speculator H.L. Williams founded the town of Summerland. In 1888 he divided his land tract, on a moderately sloping hill facing the ocean, into numerous parcels. He promoted the tiny lots – 25 x 60 – to fellow spiritualists, who bought them in quantity and moved to the area. The houses they built included bizarre architectural features such as doors which opened to walls, and stairways ascending to nowhere. The spiritual center of the town was a community séance room, demolished only when Highway 101 was put through in the 1950s.
In the 1890s, oil development began in the coastal area of Summerland, at the Summerland Oil Field. Numerous wooden oil derricks were built on the beach, and on piers stretching into the ocean. The world’s first offshore oil well, drilled into the sea floor, was at this location. Production at this beach area peaked before 1910, although most of the rigs remained into the 1920s. Peak production from the onshore portion of the Summerland Field did not actually occur until 1930; the last oil was pumped from the nearshore region in 1940. In 1957, Standard Oil Co. of California (now Chevron) found the large Summerland Offshore Oil Field, several miles offshore, which was shut down in the 1990s.
Summerland is located on the coast directly east of the city of Santa Barbara and west-northwest of the city of Carpinteria, and is almost entirely surrounded by the unincorporated community of Montecito. Summerland has a significantly higher population density than the surrounding area. U.S. Route 101 goes through Summerland.
According to the United States Census Bureau, the CDP has a total area of 2.0 square miles (5.2 km²), of which, 2.0 square miles (5.1 km²) of it is land and 0.33% is water.
This region experiences warm (but not hot) and dry summers, with no average monthly temperatures above 71.6 °F. According to the Köppen Climate Classification system, Summerland has a warm-summer Mediterranean climate, abbreviated “Csb” on climate maps.