The U.S. Geological Survey has estimated that the Appalachian region of the eastern United States holds approximately 2.3 million metric tons of undiscovered, economically recoverable lithium — a quantity sufficient to replace 328 years of U.S. imports at last year's level. The findings, published in a new USGS scientific paper in Natural Resources Research, were announced on April 28, 2026, from Reston, Virginia.
The southern Appalachians account for an estimated 1.43 million metric tons of lithium oxide, concentrated in the Carolinas, while the northern Appalachians hold an estimated 900,000 metric tons, with the largest concentrations in Maine and New Hampshire. The lithium is present in pegmatites, large-grained rocks similar to granite formed by the same geological forces that built the mountains more than 250 million years ago.
To illustrate the scale of the find, the USGS noted that the estimated 2.3 million metric tons of lithium oxide in the region would be sufficient for batteries in 130 million electric vehicles, 1.6 million grid-scale batteries large enough to stabilize an electric grid, 180 billion laptops — equivalent to a 1,000-year supply for the world at 2025 levels — or 500 billion cellphones, equivalent to 60 per person on earth.
The estimates are presented at the 50% confidence level. In the northern Appalachians alone, the USGS states there is 90% confidence of at least 90,000 metric tons, and a 10% probability of as much as 7.4 million metric tons remaining undiscovered. The median estimate of 1.4 million metric tons of resource in place was then screened for economic recoverability based on global lithium mining experience and lithium prices.
The United States currently has one sole domestic lithium producer and relied on imports for more than half the lithium used last year — factors that contributed to lithium's inclusion on the 2025 List of Critical Minerals published by the USGS. While Australia is the world's largest lithium producer, China ranks second and accounts for the majority of world lithium refining and consumption. The USGS projects that world production capacity will double by 2029.
USGS Director Ned Mamula said the research "shows that the Appalachians contain enough lithium to help meet the nation's growing needs — a major contribution to U.S. mineral security, at a time when global lithium demand is rising rapidly." He added that the United States was the dominant world producer of lithium three decades ago and that the findings "highlight the abundant potential to reclaim our mineral independence." Details from the southern Appalachian assessment, covering the region from Maryland to Alabama, are to be published separately.
This article is based on a verified primary source. The text was editorially reviewed and fact-checked prior to publication.
