Short answer
California's largest oil and gas companies are its refiners, led by Marathon Petroleum's Los Angeles refinery (365,000 barrels a day) and Chevron's El Segundo and Richmond plants, on the California Energy Commission's list of 11 refineries. California Resources of Long Beach, with $3.67 billion of 2025 revenue, calls itself the largest operator in California. Census County Business Patterns counted 393 oil and gas establishments in the state in 2023, 156 of them in Kern County.
- 11 refineries with 1,338,171 barrels a day of capacity are on the California Energy Commission's July 2026 list.
- 61.1% of the crude supplied to California refineries in 2025 was foreign, 22.9% Californian and 16.0% Alaskan.
- California's crude output fell from 395,000 barrels a day in 2020 to 288,000 in 2025, 8th among states (EIA).
- Refinery establishments employ 6,734 people at average pay of $171,905, more than any other oil and gas segment in the state.
- California Resources closed its Berry merger on 18 December 2025 and ended the year with about 2,500 employees.
On this page
This report is for job seekers, contractors and suppliers looking at California's oil and gas companies, analysts tracking a shrinking producing industry, and B2B sellers whose customers are refineries, producers and the service firms around them.
California's refineries
The California Energy Commission (CEC) lists the state's operating refineries. As of 8 July 2026:
| Refinery | Owner | Capacity (barrels a day) |
|---|---|---|
| Los Angeles | Marathon Petroleum | 365,000 |
| El Segundo | Chevron U.S.A. | 269,000 |
| Richmond | Chevron U.S.A. | 245,271 |
| Torrance | PBF Energy | 160,000 |
| Martinez | PBF Energy | 156,400 |
| Wilmington | Valero Energy | 85,000 |
| Bakersfield | Kern Energy | 26,000 |
| Bakersfield | San Joaquin Refining | 15,000 |
| South Gate | Lunday Thagard | 8,500 |
| Wilmington asphalt refinery | Valero | 6,300 |
| Kern | Talley Asphalt | 1,700 |
The total is 1,338,171 barrels a day. The US Energy Information Administration (EIA) counted 1,499,171 barrels a day of operating capacity in California on 1 January 2026; the two agencies count at different dates and on different bases, so use the CEC list for which plants are running now. Of the 483,849 thousand barrels of crude supplied to California refineries in 2025, the CEC reports 61.1% came from abroad, 22.9% from California and 16.0% from Alaska.
The producers
EIA puts California's crude oil production at 288,000 barrels a day in 2025, 8th among states and down 27% from 395,000 in 2020. Marketed natural gas fell from 155,979 million cubic feet to 111,955 over the same years.
California Resources (CRC), based in Long Beach, says in its 2025 10-K that it is "the largest operator in California." The filing reports:
- Total operating revenues of $3.67 billion in 2025.
- Average net production of about 138,000 barrels of oil equivalent a day, 79% oil, from 68 fields and about 22,000 net operated wells.
- The Berry merger, closed on 18 December 2025, which added C&J Well Services, described as one of the largest upstream well servicing and abandonment businesses in California.
- About 2,500 employees at year-end, up from about 1,550, with about 640 at C&J.
- An expectation that new well permitting would resume in Kern County in early 2026.
Other SEC registrants based in California are small or produce elsewhere. Royale Energy of El Cajon reported $1.95 million of 2025 revenue, and Okmin Resources is in Encino. Kolibri Global Energy of Thousand Oaks files a 40-F as a Canadian issuer, and its US subsidiary, which gives a Thousand Oaks address, filed 7 new-drill permits in Oklahoma in 2026 to 29 October, by Oklahoma Corporation Commission records. Phoenix Energy One gives Irvine as its principal executive office in its 2025 10-K, with $687.2 million of revenue, but drills mainly in the Williston Basin of North Dakota and Montana and in Wyoming.
California in Census data
US Census Bureau County Business Patterns (CBP) 2023, State of California, NAICS 211 (Oil and Gas Extraction), 213111 (Drilling Oil and Gas Wells), 213112 (Support Activities for Oil and Gas Operations) and 324110 (Petroleum Refineries):
| Measure (2023) | California |
|---|---|
| Establishments | 393 |
| Employees, payroll and average pay | Not reported (high-noise figure) |
| Share of US establishments | 2.35% of 16,710 |
| Rank among states | 10th |
The Census Bureau published the statewide employee and payroll totals but flagged them as high-noise: the noise it adds for confidentiality changed them by 5% or more, so we don't report them. By size, 191 establishments have 1 to 4 employees; the other classes aren't published for the four codes combined.
| Segment (NAICS) | Establishments | Employees | Average annual pay |
|---|---|---|---|
| Support activities (213112) | 199 | 3,828 | $91,269 |
| Crude petroleum extraction (211120) | 106 | 4,085 | $170,700 |
| Drilling (213111) | 51 | Not reported | Not reported |
| Natural gas extraction (211130) | 19 | Not reported | Not reported |
| Petroleum refineries (324110) | 18 | 6,734 | $171,905 |
| County | Establishments | Of which support (213112) |
|---|---|---|
| Kern County | 156 | 91 |
| Los Angeles County | 68 | 26 |
| Ventura County | 25 | 19 |
| Orange County | 24 | 10 |
| Santa Barbara County | 14 | 0 |
| Contra Costa County | 7 | 0 |
County employee totals are mostly flagged high-noise, so they aren't shown. Kern County, the San Joaquin Valley's oil county, has 40% of the state's establishments; Los Angeles County has 7 of the refinery establishments and Kern 4. These are establishments with paid employees, not companies; the self-employed aren't counted, and head offices are often filed under management of companies (NAICS 55).
Finding and checking companies
| Source | What it gives you |
|---|---|
| CEC refinery list | Every operating refinery, owner and capacity |
| CEC crude supply sources | Where refinery crude comes from, by year |
| California Independent Petroleum Association | Independent producers, royalty owners and service and supply companies, based in Sacramento |
| Western States Petroleum Association | The industry association for the western states, based in Sacramento |
| California Resources 2025 10-K | Fields, wells, permitting and headcount for the largest producer |
Well and operator records are kept by the state's Geologic Energy Management Division (CalGEM). Its website refused our connections on 30 October 2026, so check it directly before you rely on an operator's status.
Selling to California oil and gas companies
| Account type | How many | Who usually decides |
|---|---|---|
| Refineries | 11 on the CEC list | Maintenance, reliability and turnaround planners; site procurement |
| Large producer | California Resources and its C&J Well Services unit | Field operations, well servicing and abandonment managers |
| Support contractors | 199 establishments, 91 in Kern County | Owner, district manager, HSE manager |
Two kinds of work are growing while production shrinks: refinery maintenance, because the plants that remain run harder, and well servicing and abandonment, which CRC's own 10-K singles out.
Illustrative example. The seller and its prices are invented; the refinery list is the CEC's.
Golden Gauge (goldengauge.example) inspects pressure vessels and piping during refinery turnarounds. Its whole addressable list is 11 plants. With three contacts at each (turnaround manager, inspection supervisor, maintenance manager) that's 33 people. At a 10% reply rate, about 3 conversations; one turnaround contract at $600,000 makes the year. Turnarounds are planned well ahead, so the seller times outreach to each plant's next scheduled shutdown rather than to the calendar. Bebop can research each plant's owner and the people who run maintenance; the account research guide covers what to look for.
Next step: see how California's producers compare with the largest in the country in the list of the largest oil and gas companies.
Sources
- County Business Patterns (CBP), 2023, US Census Bureau, accessed 30 October 2026
- California's oil refineries, California Energy Commission, as of 8 July 2026
- Oil supply sources to California refineries, California Energy Commission, accessed 30 October 2026
- California Resources Corporation Form 10-K, fiscal 2025, SEC EDGAR, 2 March 2026
- Phoenix Energy One Form 10-K, fiscal 2025, SEC EDGAR, 17 March 2026
- Intent to drill master file, Oklahoma Corporation Commission, downloaded 30 October 2026
- Crude oil production by state, annual, US Energy Information Administration, released 30 September 2026
- Refinery Capacity Report, Table 3: capacity by state as of 1 January 2026, US Energy Information Administration, 2026
- California Independent Petroleum Association, CIPA, accessed 30 October 2026
Written by the Bebop team at Blackpearl Group. Published .
Questions people ask
What is the largest oil company in California?
California Resources Corporation, based in Long Beach, says in its 2025 10-K that it is the largest operator in California, with about 138,000 barrels of oil equivalent a day of net production from 68 fields and $3.67 billion of revenue. By refining capacity, the largest plants are Marathon Petroleum's Los Angeles refinery and Chevron's El Segundo and Richmond refineries, on the California Energy Commission's list.
How many oil refineries are in California?
The California Energy Commission listed 11 operating refineries as of 8 July 2026, with 1,338,171 barrels a day of capacity in all. The largest are Marathon Petroleum's Los Angeles refinery (365,000 barrels a day), Chevron's El Segundo (269,000) and Richmond (245,271) refineries and PBF Energy's Torrance (160,000) and Martinez (156,400) refineries. Census data counts 18 refinery establishments.
How many oil and gas companies are in California?
Census County Business Patterns counted 393 oil and gas extraction, drilling, support and refining establishments in California in 2023, 10th among states, with 156 in Kern County and 68 in Los Angeles County. That counts locations with paid employees, not companies. The statewide employee total isn't reported because the Census Bureau flagged it as a high-noise figure.
Is California oil production declining?
Yes. The US Energy Information Administration puts California's crude oil output at 288,000 barrels a day in 2025, down from 395,000 in 2020, and its marketed natural gas at 111,955 million cubic feet, down from 155,979. California Resources' 10-K said it expected new well permitting to resume in Kern County in early 2026.
Where does California's crude oil come from?
Most of it is imported. The California Energy Commission reports that of 483,849 thousand barrels of crude supplied to California refineries in 2025, 61.1% came from foreign sources, 22.9% from California and 16.0% from Alaska. The Commission notes that the California figure may include small amounts from North Dakota and the Gulf Coast states.