Lithium in Eastern States Could Replace Imports for a Century or More

The southern Appalachians hold an estimated 1.43 million metric tons of lithium oxide, concentrated in the Carolinas, and the northern Appalachians hold an estimated 900,000 metric tons, concentrated in Maine and New Hampshire, according to estimates in a new USGS scientific paper published in Natural Resources Research. The lithium is present in pegmatites, large-grained rocks similar to granite.

"This 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," said USGS Director Ned Mamula. "USGS mineral science is the leading edge in the effort to restore America's mineral independence by mapping our nation's mineral resources. Everything else follows on the science: permitting reform and other policy changes to support investment in clean, responsible mining to 21^st century standards, and mining workforce training for new American jobs. 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."

The United States had one sole producer of lithium and relied on imports for more than half the lithium used last year, factors that contributed to its inclusion on the 2025 List of Critical Minerals published by the USGS. Lithium is used in the lithium-ion batteries that power computers, military equipment, vehicles, phones, electric tools, and energy-grid storage, as well as in aerospace alloys. Additional lithium is imported into the United States every year inside finished products made elsewhere and containing lithium-ion batteries. While Australia is the world's largest producer of lithium, China is second, and accounts for the majority of world lithium refining and consumption.

The USGS projects that world production capacity for lithium will double by 2029, driven by increasing demand. Lithium supply security has become a priority for technology companies.

The estimated 2.3 million metric tons of lithium oxide in the Appalachian region would be enough lithium for batteries in:

• 1.6 million grid-scale batteries large enough to stabilize an electric grid
• 130 million electric vehicles
• 180 billion laptops, or a 1,000 year-supply of laptops for the world (at 2025 levels)
• 500 billion cellphones, or 60 cellphones for each person on earth

Assessing the mineral resources of the United States has been a responsibility of the USGS since it was created in 1879. Its mission was reinforced in the Energy Act of 2020, which called on the USGS to assess all minerals and the USGS is playing a major role in implementing Executive Orders14154, Unleashing American Energy, and 14241, Immediate Measures to Increase American Mineral Production.

Longstanding USGS Fundamental Science Practices and Executive Order 14303 Restoring Gold Standard Science emphasize the importance of scientific peer review and communication of the uncertainty of scientific findings. The estimates in these studies present the 50% confidence level. For example, in the northern Appalachians, it is equally likely that there are more than 1.4 million metric tons of lithium oxide as it is that there is less. There is 90% confidence of at least 90,000 metric tons, and a 10% probability that there are as much as 7.4 million metric tons that remain undiscovered in the northern Appalachians alone. 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.

Lithium pegmatites in the Appalachian region have long attracted scientific attention - the Kings Mountain area of North Carolina was the site of the first large-scale lithium pegmatite mining in the United States, and large Maine deposits have been studied. The new USGS assessments build on that legacy with a more systematic, detailed approach.

A team of USGS geologists worked together on the northern and southern assessments, combining geologic maps, tectonic history, geochemical sampling, geophysical surveys, and records of mineral occurrences. They then conducted simulations using a global dataset for lithium pegmatites to estimate how many undiscovered lithium deposits there are in the study area, and how much lithium they hold. Details from the southern assessment covering the Appalachians from Maryland to Alabama will be published later.

Lithium-rich pegmatites in the northern Appalachians formed from the same geologic forces that built the mountains more than 250 million years ago. The high heat and pressure during the mountain-building caused some of the deeper crustal rocks to melt, and some of these magmas were rich in lithium. This melting occurred when plate tectonics forced Africa, Europe, and North America together into a supercontinent named Pangea. Pegmatites like the ones found in the Appalachian mountain belt are found in corresponding areas of Ireland and Portugal, both of which formerly bordered the Appalachians.

The USGS also studies and assesses other sources of lithium, including in wastes from energy production. In 2024, USGS researchers assessed that a resource of 5 to 19 million metric tons of lithium is present in brines in the Smackover Formation of southwest Arkansas. The USGS did not assess what amount would be economically recoverable.