California's nearly 100 terminals receive petroleum and petroleum products by tanker, barge, pipeline, rail, or truck. Most of California's terminals are marine terminals. At these facilities petroleum or product is transferred from or to tankers or barges. Tankers loaded with Alaska North Slope petroleum, for example, enter marine terminals in northern and southern California, where the crude oil is then sent to refineries by pipeline for processing. An example of pipeline receipts of petroleum at a terminal is heavy California petroleum produced in the Bakersfield area that is sent by pipeline to a refinery at Martinez.

Terminals also serve as refiner's wholesale distribution points for products. Product, such as gasoline, is sold to distributors (jobbers) who then sell to consumers through the distributors' own retail stations. The distributor may also resell the gasoline to other station dealers. Gasoline can also be sold directly to station dealers from the terminal. The marketing structure differs depending on the type of product being sold.

A terminal can be linked with several refineries and storage facilities and be supplied by privately-owned pipelines or a common carrier line. Total capacity at a terminal can range from a few thousand barrels to a few million barrels. The most apparent equipment at a terminal are the tanks used for storage and separation of different product grades. The number of tanks can range from a few to more than 70. Other equipment found includes piping, pumps, valves, and meters needed for bulk receipts and for loading racks used for small deliveries to trucks. Marine terminals have vessel length and water depth limits that dictate the size of tankers that can off-load at the facility.