A funny thing about the US oil business is that the biggest companies do not all make money in the same way. ExxonMobil drills for oil, refines it and sells fuels. Valero spends far more of its time refining crude than producing it. Kinder Morgan barely fits the picture people usually have of an “oil company” because pipelines and storage sit at the centre of its business.

So a useful list has to look beyond sales. Production, refinery size, pipeline networks, major US assets and recent deals all tell part of the story.

Here are 10 companies that currently have a major place in the American oil and gas industry.

Top 10 Oil & Gas Companies in USA at a Glance

Rank	Company	Main Business
1	ExxonMobil	Oil and gas production, refining, chemicals
2	Chevron	Oil and gas production, refining
3	ConocoPhillips	Oil and gas production
4	Marathon Petroleum	Refining and midstream
5	Valero Energy	Refining and fuels
6	Phillips 66	Refining, pipelines and chemicals
7	Occidental Petroleum	Oil and gas production
8	EOG Resources	US shale production
9	Kinder Morgan	Pipelines and storage
10	Enterprise Products Partners	Pipelines, terminals and storage

1. ExxonMobil

ExxonMobil still does more under one roof than most American energy companies. It produces crude oil and natural gas, owns refineries, sells fuel and runs a large chemicals business. LNG has also become a bigger part of the company over the years.

The Pioneer Natural Resources acquisition gave Exxon an even larger position in the Permian Basin. In 2025, the company averaged about 4.7 million barrels of oil equivalent per day, its highest annual production in more than 40 years. Roughly 1.6 million barrels of oil equivalent per day came from the Permian, while projects in Guyana added another large source of output.

Exxon also made $28.8 billion in profit during 2025. Lower oil prices pulled that number down from the previous year, but the company still spent heavily on drilling and large projects.

Its size comes partly from owning businesses at several stages of the oil chain. Exxon can produce crude, process it in its own refineries and then make fuel or chemical products from the same supply.

2. Chevron

Chevron spent much of 2025 finishing a deal that had already attracted years of attention. The company finally completed its purchase of Hess and picked up one of the most valuable oil positions in the process.

Hess owned a 30% share of Guyana’s Stabroek Block, where companies have discovered more than 11 billion barrels of recoverable resources. Chevron also gained Hess assets in the Bakken and other producing regions.

The acquisition helped push Chevron’s production to a record 3.7 million barrels of oil equivalent per day in 2025, around 12% above the previous year. Its Permian production also moved past one million barrels per day.

Chevron and Exxon remain the two American companies most people think of when they picture a traditional global oil major. Both drill, refine and operate in several countries, which gives them far more variety than a producer tied mainly to one US shale basin.

3. ConocoPhillips

ConocoPhillips took a different path years ago. Instead of keeping a large refining business, it concentrated on producing oil and natural gas.

That has left it with a simpler business than Exxon or Chevron, but certainly not a small one. ConocoPhillips averaged 2.375 million barrels of oil equivalent per day in 2025, including about 1.484 million barrels from the Lower 48 states.

Its purchase of Marathon Oil in late 2024 added more producing acreage and pushed the company further into major US shale regions. By the end of 2025, ConocoPhillips said the combined operation had already produced more than $1 billion in annual run-rate savings.

The Permian, Eagle Ford and Bakken make up a big part of its US business. Since ConocoPhillips does not have a giant refining arm to balance the company, oil and gas prices have a more direct effect on how the business performs.

4. Marathon Petroleum

Marathon Petroleum and Marathon Oil still get mixed up, even though they have been separate companies for years. ConocoPhillips bought Marathon Oil, while Marathon Petroleum stayed independent and kept running one of the largest refining systems in the country from its headquarters in Findlay, Ohio.

In 2025, Marathon had about 2.963 million barrels per day of refining capacity, and its refineries ran at an average utilization rate of 94% during the year. That puts the company close to the top of the US refining market by sheer processing capacity.

Marathon does not need to be one of the country’s biggest crude producers to play a major role in the oil business. Refineries take crude and turn it into gasoline, diesel, jet fuel and other products that actually reach consumers and businesses.

The company also has a large interest in MPLX, which owns pipelines, terminals and natural gas processing assets. That gives Marathon access to more of the infrastructure around refining, from moving feedstock into plants to sending finished fuels out into the market.

5. Valero Energy

Valero Energy built its business around refining, and that remains the part of the company that matters most.

The San Antonio-based company runs 14 petroleum refineries across the United States, Canada and the UK, with roughly 3 million barrels per day of throughput capacity. Valero also describes itself as the world’s largest independent refiner.

Most of its refining footprint is in the United States, with major plants in Texas, Louisiana, Oklahoma and several other states. The company also operates 12 ethanol plants in the US, giving it about 1.7 billion gallons of annual ethanol production capacity.

Its refinery count changed recently. Valero finished idling the processing units at its Benicia refinery in California in April 2026, so older lists that still show 15 active refineries are now out of date.

Consumers may know Valero from fuel stations, but the retail name only shows a small part of the business. The company’s real size comes from processing enormous amounts of crude and selling the fuels and products that come out of those refineries.

6. Phillips 66

Phillips 66 became a separate company in 2012, when ConocoPhillips split off its refining, marketing and other downstream businesses.

Since then, Phillips 66 has grown into much more than a refinery operator. Refining still accounts for a large part of the business, but pipelines, natural gas liquids, terminals and chemicals now bring in a significant amount of its revenue as well.

In 2025, the company strengthened that side of the business by expanding its midstream operations and taking full ownership of the Wood River and Borger refineries after buying the remaining interest in WRB Refining.

Phillips 66 earned about $4.4 billion in 2025, while its refineries ran at a 99% crude capacity utilization rate during the fourth quarter. Its natural gas liquids business also reached record transportation and fractionation volumes during the year.

So while many people still think of Phillips 66 mainly as a refining company, the business today spreads across several parts of the energy system, especially pipelines and natural gas liquids.

7. Occidental Petroleum

Occidental Petroleum, usually called Oxy, has spent the last several years reshaping itself around oil and gas production.

The company already had a huge Permian Basin presence before buying CrownRock in 2024. By 2025, US production averaged about 1.2 million barrels of oil equivalent per day, with roughly 786,000 coming from the Permian alone. Worldwide production averaged 1.434 million barrels of oil equivalent per day.

Occidental made another big change at the beginning of 2026 when it completed the sale of OxyChem. The sale helped the company reduce debt by billions of dollars and left the oil and gas side even more central to the business.

Oxy still works outside the Permian, including the Rockies, Gulf of America and international projects, but West Texas remains the part of the map most closely tied to its current production.

8. EOG Resources

EOG Resources does not have gas stations or a famous consumer fuel brand, which is one reason people outside the industry may know the name less well.

Inside US shale, it is hard to miss.

EOG has major operations in the Delaware Basin, Eagle Ford and Utica, along with other US and international assets. The company generated $22.6 billion in revenue and $5 billion in net income in 2025.

It also made a large move into the Utica shale during the year by buying Encino Acquisition Partners. EOG paid about $4.48 billion in cash and assumed roughly $1.2 billion of Encino debt.

By the third quarter of 2025, EOG’s total production had climbed above 1.3 million barrels of oil equivalent per day. The company still gets much of its identity from its US shale operations rather than refining or retail fuel.

9. Kinder Morgan

Kinder Morgan does not need to own every molecule of natural gas moving through its system to make money from it.

Pipelines are the business.

Kinder Morgan owns an interest in or operates about 65,000 miles of natural gas pipelines, and the company says roughly 40% of the natural gas consumed in the United States travels through its network.

Its petroleum-products business adds another 9,500 miles of pipeline and moves around 2.4 million barrels of gasoline, diesel, jet fuel, crude and condensate each day.

That puts Kinder Morgan in a very different position from an oil producer. Exxon worries directly about how many barrels a well produces. Kinder Morgan makes much of its money by transporting and storing energy after somebody else has already produced it.

Natural gas demand from power plants, LNG export facilities and industry has kept those networks important, even as the public conversation around energy changes.

10. Enterprise Products Partners

Enterprise Products Partners is another company that rarely appears in front of ordinary consumers but sits right in the middle of the US energy system.

Enterprise owns more than 50,000 miles of pipelines, over 300 million barrels of storage capacity and natural gas storage facilities. Its assets handle natural gas, crude oil, natural gas liquids, petrochemicals and refined products.

The company earned $5.8 billion for common unitholders in 2025 and generated $7.9 billion in operational distributable cash flow. It also marked its 27th straight year of increasing distributions to investors.

Enterprise has especially deep ties to the Gulf Coast, where pipelines, storage caverns, processing plants and export terminals all meet. That infrastructure gives producers a route from inland fields to refineries, chemical plants and ships leaving the United States.

It does not drill like ConocoPhillips or refine like Valero, but the oil and gas business would have a hard time functioning at its current scale without companies doing this middle part.

Oil Producer, Refiner or Pipeline Company: What Is the Difference?

The phrase “oil and gas company” covers several completely different businesses.

ExxonMobil, Chevron, ConocoPhillips, Occidental and EOG all spend heavily on producing oil and natural gas. Exxon and Chevron continue further down the chain into refining, while ConocoPhillips and EOG stay much more focused on production.

Marathon Petroleum, Valero and Phillips 66 sit closer to the refining side. They buy crude or other feedstocks and turn them into gasoline, diesel, jet fuel and other products.

Then companies such as Kinder Morgan and Enterprise Products Partners handle the pipes, terminals and storage facilities that connect fields, refineries and export markets.

That is why simply sorting these companies by sales can give a strange picture of who actually produces the most oil.

Which Is the Largest US Oil Company?

By overall scale among US-headquartered oil majors, ExxonMobil and Chevron sit in a class of their own.

Exxon produced about 4.7 million barrels of oil equivalent per day in 2025, compared with Chevron’s record 3.7 million. Both operate globally and combine upstream production with downstream businesses.

ConocoPhillips comes next as a very large independent producer, but it does not run the same type of integrated refining and chemicals business.

The answer changes if the question is about refining rather than crude production. Marathon Petroleum runs roughly 3 million barrels per day of refining capacity, while Valero also operates at close to that level.

Why Texas Appears Everywhere on This List

There is a reason so many of these companies either call Texas home or keep major operations there.

The Permian Basin has turned West Texas and southeastern New Mexico into one of the world’s most important oil-producing areas. ExxonMobil, Chevron, Occidental, ConocoPhillips and EOG all have large positions there.

Move east toward Houston and the Gulf Coast, and the business changes. Refineries, chemical plants, LNG facilities, pipelines and export terminals crowd the region because ships can carry oil, gas and refined products into global markets from there.

That is also why ExxonMobil, Chevron, Phillips 66, Occidental, Kinder Morgan and Enterprise Products Partners all have headquarters or major corporate operations in the Houston area.

Frequently Asked Questions

What is the biggest oil and gas company in the USA?

ExxonMobil remains one of the largest US-headquartered oil and gas companies by production and overall business scale. It averaged about 4.7 million barrels of oil equivalent per day in 2025 and earned $28.8 billion for the year.

What are the top oil companies in the United States?

Some of the largest names include ExxonMobil, Chevron, ConocoPhillips, Occidental and EOG Resources. Marathon Petroleum, Valero and Phillips 66 also rank among the country’s major energy companies because of their huge refining operations.

Which US company produces the most oil and gas?

Among the companies covered here, ExxonMobil reported the largest total oil-equivalent production in 2025 at about 4.7 million barrels per day. Chevron followed with roughly 3.7 million barrels per day.

Which is the largest US oil refiner?

Marathon Petroleum operates one of the largest refining systems in the United States, with around 2.96 million barrels per day of crude refining capacity in 2025. Valero also runs close to 3 million barrels per day of throughput capacity across its current refinery network.

Is ConocoPhillips the same company as Phillips 66?

No. ConocoPhillips separated its downstream operations into Phillips 66 in 2012. ConocoPhillips now focuses mainly on oil and gas production, while Phillips 66 works heavily in refining, midstream and chemicals.

Did ConocoPhillips buy Marathon Petroleum?

No. ConocoPhillips bought Marathon Oil, not Marathon Petroleum. Marathon Petroleum remains a separate refining company based in Ohio.

What does Kinder Morgan do?

Kinder Morgan mainly owns and operates pipelines and storage assets. Its natural gas network stretches about 65,000 miles and carries roughly 40% of the natural gas consumed in the United States.