Almost 400 million barrels of oil are currently sitting in dozens of deep underground caverns in the Deep South of the US. It’s known as the Strategic Petroleum Reserve (SPR), and it serves as a big fat pawn in the high-stakes game of geopolitics.
Scattered across 61 caverns in Texas and Louisiana along the Gulf Coast, the subterranean storehouse currently holds 396.4 million barrels of crude oil, according to official statistics from March 28, 2025. Today, it has a maximum capacity of 714 million barrels, though historically, it has held even more. Capacity peaked in December 2009 at a record 726.6 million barrels.
The stores are located 610 to 1,219 meters (2,000 to 4,000 feet) below the Earth’s surface in salt domes, vast underground formations formed by the slow upward movement of salt through overlying rock layers. These domes offer a secure environment that prevents leaks and contamination, making them an ideal choice for crude oil storage. It’s also apparently much cheaper than constructing artificial storage domes or digging caverns.
The oil doesn’t just sit here idle. Millions of barrels are regularly moved in and out to strategically maintain the US’s strong position both at home and on the international stage (at least, that’s the idea).
Map showing the location of the Strategic Petroleum Reserves in Texas and Louisiana, USA, in 2018.
The SPR was set up in the wake of the 1973 energy crisis when a coalition of Arab states imposed a strict embargo against the US and other countries that had backed Israel during the 1973 Yom Kippur War. The bold move sent shockwaves through the global economy – skyrocketing prices, economic turmoil, and long lines at gas stations – and made the US realize how vulnerable it was to upsets in foreign oil supply.
In response, the SPR was set up by the government as an emergency oil stockpile to safeguard against supply disruptions caused by natural disasters, geopolitical conflicts, trade route closures, shaky international markets, and so on. Private oil companies do have their own emergency reserves that can roll with the punches of a supply run issue, but nothing on this scale.
Managed by the US Department of Energy, the SPR is able to release oil to the US market to ease shortages and lower prices or sell it to other nations when strategically necessary. For instance, in the wake of Hurricane Katrina in 2005, the reserve released 20.8 million barrels to offset supply disruptions and stabilize prices. If the government hadn’t taken that action, Americans would likely have had to pay more at the gas pump.
There have been dozens of releases from the SPR over the past decades, at least four of which came directly from the orders of the President. The most recent was in March 2022, following Russia’s invasion of Ukraine, when the US coordinated with 30 other countries to release 60 million barrels of oil from strategic reserves, with the US contributing half of the load. This collective action aimed to stabilize global energy markets amid significant supply disruptions caused by Russia, a major global supplier of fossil fuels.
However, the whole system around SPR attracts a bunch of criticism from all angles. Some argue that it is inefficient and badly organized. This was highlighted in October 2000 when the SPR auctioned off significant allocations to smaller and relatively unknown firms with little-to-no experience in oil markets. Others have contended it has been used for self-serving political maneuvering. For instance, commentators accused President Biden of ordering emergency releases in 2022 to lower gas prices and curry favor with voters ahead of the midterm elections.
As the world’s energy landscape changes and international affairs become increasingly messy, some experts are beginning to ponder whether the SPR needs a massive revamp or a total overhaul.
