Appalachian Mountains May Hold Vast Untapped Lithium Reserves

The ancient Appalachian Mountains may be hiding one of the United States' most valuable untapped natural resources. According to new research by the US Geological Survey (USGS), the mountain range contains an estimated 2.5 million tons of lithium, enough to manufacture around 500 billion smartphones, 180 billion laptops or 130 million electric vehicles. The discovery highlights the enormous potential of one of North America's oldest mountain systems at a time when demand for battery materials is soaring. Researchers say the vast reserves could play an important role in strengthening future domestic supplies, although developing them would come with significant technical and environmental challenges.

How much lithium is hidden beneath the Appalachian Mountains?

Researchers estimate that the Appalachian Mountains, stretching from Alabama to Maine, contain around 2.5 million tons (2.3 million metric tons) of lithium locked inside coarse-grained igneous rocks known as pegmatites. According to the USGS, the resource would be enough to replace US lithium imports for approximately 328 years if imports remained at last year's level. The estimate comes from two studies covering the northern and southern Appalachians, marking the first comprehensive USGS assessment of lithium resources across the region. To reach their findings, scientists analysed geological maps, geochemical and geophysical data, records of known mineral occurrences and the area's tectonic history. They also used a global dataset of lithium-bearing pegmatites to model the likely distribution and size of undiscovered deposits. Both studies were published in the journal Natural Resources Research.

Where the largest deposits are located

The northern Appalachian region, which includes parts of Maine, New Hampshire, Vermont, New York, Massachusetts, Connecticut, Rhode Island, Pennsylvania, New Jersey and Delaware, is estimated to contain around 990,000 tons of lithium. Several deposits in Maine, including the Plumbago North pegmatite, contain spodumene, the world's primary hard-rock source of lithium because of its high lithium concentration and well-established extraction process. Meanwhile, the southern Appalachians, spanning parts of Maryland, Virginia, North Carolina, South Carolina, Georgia, Tennessee and Alabama, are believed to hold around 1.57 million tons of lithium. North Carolina and South Carolina once formed the backbone of the US lithium industry, supplying much of the country's production between the 1940s and the 1990s before lower-cost imports shifted mining activity overseas.

Lithium-bearing pegmatite containing spodumene, one of the world's most important hard-rock sources of lithium.

Why lithium has become one of the world's most valuable minerals

Lithium is a vital ingredient in rechargeable batteries that power smartphones, laptops, electric vehicles and large-scale energy storage systems supporting renewable electricity grids. It is also used in aerospace alloys, military equipment, industrial lubricants and medicines prescribed for certain mood disorders. The rapid expansion of electric vehicles and renewable energy technologies has turned lithium into one of the world's most sought-after raw materials. Governments and manufacturers are racing to secure stable supplies as battery production continues to grow worldwide.

Why the discovery matters for the US

Although the United States possesses substantial lithium resources, domestic production remains limited. The country currently has only one operational lithium mine, located in Clayton Valley, Nevada, while much of the lithium used by US manufacturers is imported either as raw material or inside batteries and electronic products assembled overseas. Researchers say expanding domestic production could strengthen supply chains, improve energy security and support the country's growing battery manufacturing sector as demand continues to rise.

Mining the lithium won't be easy

Unlike lithium extracted from underground brines, pegmatite deposits require hard-rock mining, which involves blasting, excavating and crushing large volumes of rock before the lithium can be chemically processed. The process is energy-intensive and requires significant water and infrastructure. Scientists caution that large-scale mining could disturb wildlife habitats, reshape mountain landscapes and generate waste capable of contaminating nearby soil and waterways if not carefully managed. Future projects would also need to undergo extensive environmental reviews and permitting before commercial production could begin.

A valuable resource with difficult choices ahead

The USGS assessment offers one of the clearest pictures yet of the Appalachian Mountains' lithium potential, but researchers stress that identifying a resource does not automatically make it economically recoverable. Extraction costs, environmental regulations, infrastructure, land ownership and community support will all determine whether these deposits are eventually developed. Even so, the findings underscore the strategic importance of the ancient mountain range as countries compete to secure the battery materials needed for the clean energy transition. If developed responsibly, the Appalachian Mountains could become a significant contributor to America's future lithium supply while helping meet growing demand for next-generation technologies.