The Monterey Formation is an extensive Miocene oil-rich geological sedimentary formation in California, with outcrops of the formation in parts of the California Coast Ranges, Peninsular Ranges, and on some of California's off-shore islands. The type locality is near the city of Monterey, California. The Monterey Formation is the major source-rock for 37 to 38 billion barrels of oil in conventional traps such as sandstones. This is most of California's known oil resources. The Monterey has been extensively investigated and mapped for petroleum potential, and is of major importance for understanding the complex geological history of California. Its rocks are mostly highly siliceous strata that vary greatly in composition, stratigraphy, and tectono-stratigraphic history.

The Orcutt Oil Field is a large oil field in the Solomon Hills south of Orcutt, in Santa Barbara County, California, United States. Discovered in 1901 by William Warren Orcutt, it was the first giant field to be found in Santa Barbara County, and its development led to the boom town of Orcutt, now the major unincorporated southern suburb of Santa Maria. With a cumulative production in 2008 of 870,000 barrels (138,000 m3) of oil, it is the largest onshore producing field in Santa Barbara County.