Oil refineries in the US: how refining works and who runs it

The U.S. refinery fleet in numbers

EIA counted 130 operable petroleum refineries in the United States as of January 1, 2026. The same EIA source identifies Motiva's Port Arthur, Texas, refinery as the largest U.S. refinery, with a capacity of 656,400 barrels per calendar day as of that date. Detailed capacity by facility, company, and process unit is published in EIA's annual Refinery Capacity Report, which is the primary reference for anyone who needs plant-level numbers rather than headlines.

Those numbers describe nameplate capability, not output. Actual runs depend on maintenance schedules, unplanned outages, crude availability, product margins, and logistics. Capacity is also reported in different units — barrels per calendar day and barrels per stream day — so any comparison between plants or companies should state which measure it uses and the date of the report. When a figure appears without a date and unit, treat it as unverified.

How a refinery turns crude into products

EIA describes refining as three basic steps. Separation heats crude oil and sends it through distillation units, where components separate by boiling point into fractions. Conversion uses heat, pressure, catalysts, and sometimes hydrogen to crack heavy hydrocarbon molecules into lighter ones, producing more gasoline and distillate from each barrel. Treatment and blending combine processing streams to meet specifications such as octane and vapor pressure for finished fuels.

The mix of conversion units — often called configuration or complexity — determines which crudes a refinery can run profitably and which products it can make. A refinery with deep conversion can process heavier, higher-sulfur crude and still produce a high share of light products. A simpler plant depends more on light, sweet crude and yields more residual fuel. That is why crude differentials and product cracks matter as much as the outright crude price for a refiner's economics.

Refining companies in BTU Graph

Marathon Petroleum operates petroleum refineries along with product marketing and branded fuel distribution, renewable-fuel facilities, and marine, pipeline, and terminal logistics in the United States. Its relationship with MPLX adds gathering, processing, and transportation exposure, so researchers should separate the refining and marketing company from the midstream partnership while mapping how they integrate.

Phillips 66 operates refining alongside midstream, chemicals, marketing, specialty products, and renewable fuels, and its commercial organization supplies crude and feedstocks, markets products, manages transportation, and trades around physical assets. Valero manufactures conventional and lower-carbon transportation fuels through petroleum refineries, ethanol plants, and renewable diesel and sustainable aviation fuel activities, with a footprint linking feedstock procurement, conversion assets, logistics, and product markets in the United States, Canada, the United Kingdom, and other destination markets.

Refineries also depend on midstream partners for crude supply and product distribution. Kinder Morgan operates crude oil and refined products pipelines and liquids terminals, and Enterprise Products Partners links production to refineries, chemical plants, and export markets through pipelines, storage, and marine terminals. A refinery's logistics position can matter as much as its process configuration.

What drives refinery economics

The basic margin is the difference between what the refinery pays for crude and other feedstocks and what it receives for its products. Industry shorthand uses crack spreads — for example, a gasoline or diesel price against a crude benchmark — but realized margins depend on the specific crude slate, location differentials, product yields, secondary products, transportation costs, compliance costs, and plant reliability. Two refineries on the same coast can earn very different margins in the same month.

Seasonality and regulation add more variables. Gasoline specifications change between summer and winter grades, maintenance is clustered in spring and fall, and renewable fuel obligations and credits affect both conventional refiners and renewable fuel producers. Lower-carbon fuels such as renewable diesel and sustainable aviation fuel, which Valero and others now produce, introduce different feedstocks and credit markets alongside the petroleum business.

Outages and inventories close the loop. An unplanned shutdown at a large plant can tighten regional product supply within days, while the same event lowers local crude demand. Inventories at terminals and refineries buffer those shocks, so analysts watching a refining region usually track runs, stocks, and product prices together rather than reading any one of them alone. A margin model that ignores logistics and inventory position will tend to overstate how quickly prices respond to a single plant event.

Using refining data in practice

Teams that buy fuel, hedge exposure, or model refiners need consistent price series for crude benchmarks and products, aligned by date, unit, and currency. Oil Price API, which publishes BTU Graph, provides crude and refined-product benchmarks as structured data; internal systems should still own contract terms, inventory, and the differentials that convert a benchmark into a delivered price. Keep EIA capacity data, company disclosures, and market prices as separate, dated inputs so the analysis can be reproduced.

Companies are listed alphabetically in BTU Graph's directory, and inclusion is not an endorsement or a ranking. This guide does not list every U.S. refinery; use EIA's Refinery Capacity Report for the full facility list. Confirm current plant ownership and capacity with the latest EIA release and company filings, since refineries are sold, converted, and closed over time.