Appalachian Lithium Reserves Could Strengthen US Domestic Supply Security

USGS

Appalachian lithium reserves could give the US a much larger domestic resource base than previously recognised, according to a new assessment from the US Geological Survey. The agency said the eastern US Appalachian region may contain enough undiscovered, economically recoverable lithium to replace 328 years of US imports at 2025 levels.

Appalachian lithium reserves are hosted in pegmatites, large-grained rocks similar to granite. The southern Appalachian region is estimated to contain 1.43mn t of lithium oxide, while the northern Appalachian region holds another 0.90mn t.

Appalachian lithium reserves matter because the US still depends heavily on imported lithium. The country has only one current lithium producer and relied on imports for more than half of its supply in 2025.

The assessment adds another possible domestic supply route alongside lithium brine projects in the Smackover formation. Together, these resources could reshape US lithium strategy if they can be converted into permitted, economic and commercially scalable projects.

Pegmatite Resources Add a Hard-Rock Lithium Option

The Appalachian assessment points to hard-rock lithium potential in the eastern US. Pegmatite-hosted lithium is different from brine-based production because it usually requires mining, concentration and chemical conversion.

This gives the US another possible supply pathway. Hard-rock projects can produce spodumene concentrate, which can then be converted into lithium chemicals for batteries, energy storage and industrial uses.

Albemarle is already planning a lithium concentrator facility at Kings Mountain, North Carolina. The project is designed to produce 420,000 t/yr of lithium concentrate from spodumene.

That project is important because it could help rebuild a US hard-rock lithium supply chain. Domestic spodumene production would reduce reliance on foreign raw material and support future US conversion capacity.

However, resource estimates alone do not guarantee supply. Appalachian lithium projects would still need exploration, permitting, mine development, processing investment, environmental approvals and downstream customer qualification.

The strategic significance is still clear. The US lithium conversation is expanding beyond Nevada brines and western projects into eastern hard-rock resources with long-term supply potential.

Smackover Brines and Appalachian Pegmatites Broaden US Lithium Strategy

The Appalachian estimate follows earlier USGS work on the Smackover formation in southwest Arkansas. In 2024, the agency assessed that Smackover brines contain 5mn-19mn t of lithium, although it did not define economically recoverable volumes.

Several companies, including Equinor, ExxonMobil, EnergyX and Standard Lithium, are developing lithium projects in the Smackover region. Some are targeting commercial output around 2027.

The Smackover and Appalachian resource bases are strategically different but complementary. Smackover projects depend on brine extraction and processing technologies, while Appalachian projects would likely depend on hard-rock mining and spodumene concentration.

This diversification matters for US supply security. A lithium strategy based on multiple geological sources is more resilient than one dependent on a single basin, technology or company.

The US will still need processing capacity. Mining lithium ore or extracting lithium from brine does not automatically create battery-grade lithium carbonate or hydroxide.

That midstream gap remains the critical issue. Domestic resources must be connected to refining, chemical conversion, permitting, infrastructure and offtake agreements before they can reduce import dependence.

For battery manufacturers, the Appalachian assessment offers a long-term signal. More domestic resource potential could support future supply chains for electric vehicles, grid storage and defence-related battery applications.

The Metalnomist Commentary

The Appalachian lithium assessment is a resource-security signal, not an immediate supply solution. The US has the geology, but the decisive bottleneck will be converting resources into permitted mines, concentrators and battery-grade lithium chemicals.