Vast, Untapped Source of Lithium Found in The US Could Last 300 YearsNEWS | 15 May 2026There could be nearly 330 years' worth of lithium hiding beneath the Appalachian Mountains, which stretch like a stony spine across the eastern United States.
New research from the US Geological Survey suggests that the Appalachians may contain around 2.3 million metric tons (2.5 million US tons) of recoverable lithium oxide locked away in pegmatites, the grainy, granite-like rocks that form as water-rich magma cools and crystallizes deep within the Earth.
"This research shows that the Appalachians contain enough lithium to help meet the nation's growing needs – a major contribution to US mineral security, at a time when global lithium demand is rising rapidly," says Ned Mamula, Director of the US Geological Survey (USGS).
Therefore, mapping US mineral resources may help reverse the country's recent reliance on lithium imports.
"The United States was the dominant world producer of lithium three decades ago, and this research highlights the abundant potential to reclaim our mineral independence," Mamula adds.
The soft, silvery lithium is the lightest of the metals and the least dense of the solid elements. It's also one of the oldest elements in existence, as trace amounts were produced during the Big Bang.
Importantly, it is the primary active chemical in lithium-ion batteries, which account for 87 percent of global lithium demand.
These rechargeable batteries power our most essential devices, including smartphones, laptops, electric vehicles, and grid-scale energy storage systems, making lithium indispensable for emerging clean energy initiatives.
Accordingly, lithium demand is projected to grow over 40 times by 2040, according to the International Energy Agency (IEA).
As a result, the USGS has been tasked with assessing critical mineral deposits throughout the US.
So, as described in the recent study, USGS scientists combined various methods to assess the extent and availability of undiscovered lithium-containing pegmatite deposits in the Appalachian region of the US.
First, the researchers compiled publicly available geological and geochemical data, such as mineral maps, to pinpoint a set of "permissive tracts," or areas that are more or less likely to hold lithium deposits.
They then estimated the quantity of lithium in these potentially undiscovered reserves using the Delphi Method, a structured communication technique involving a panel of more than 20 USGS geoscientists, over a two-day period in July 2024.
The researchers also extrapolated the quality and quantity of the lithium-containing ore by drawing on data from known global lithium deposits, previously determined through methods such as mineral inventory reports.
Finally, the researchers ran 20,000 probabilistic simulations based on the above data to determine the most realistic lithium distribution scenarios, applying an economic filter to gauge how much of this lithium could be feasibly extracted.
The research suggests that 900,000 metric tons of lithium oxide may be economically extractable in the northern Appalachian region, with Maine, New Hampshire, and parts of Vermont deemed the most prospective areas.
Another 1.43 million metric tons could be extractable in the southern Appalachian region, chiefly concentrated in the Carolinas.
Together, the researchers say this huge deposit could meet the lithium needs of the US for 328 years, based on consumption and import rates in 2025.
For perspective, this could furnish every person in the world with 60 smartphones. It's also equivalent to supplying the world with laptops for 1,000 years – though by that point, computers may be more brain than machine, or embedded within our biological tissues.
These as-yet untapped reserves are not the only potentially profitable lithium reserves in the US.
An unrelated report recently described a sizable lithium concentration swirling in the salty waters of an ancient limestone aquifer beneath Arkansas, a structure known as the Smackover Formation.
Related: 'Supergiant' Gold Deposits Could Be Worth Over US$80 Billion
However, actually extracting these reserves may prove more difficult.
Should this lithium eventually make its way from beneath the northern Appalachians to beneath the cover of our smartphones, it will have completed a journey that began more than 300 million years ago with the formation of the supercontinent Pangea.
This study was published in Natural Resources Research.Author: Ivan Farkas. Source
