The Lithium Gap.
Nevada Has 40 Million Tons.
New Hampshire Has 900,000.
The United States is sitting on roughly 19 million metric tonsof lithium — about 17% of the world’s known resources, third behind only Bolivia and Argentina. Most Americans have no idea. On April 30, 2026, the U.S. Geological Survey published its first quantitative assessment of lithium pegmatite deposits in the northern Appalachian orogen: roughly 900,000 metric tons of recoverable lithium oxide under Maine and New Hampshire. Same week, construction at the McDermitt Calderaon the Nevada-Oregon border — potentially the largest lithium deposit ever identified anywhere on Earth, holding an estimated 20 to 40 million metric tons— ran past 1,000 workers, headed for 1,800 by year-end. North Carolina’s Kings Mountain district is restarting. Albemarle and Piedmont Lithium are back in the Carolinas. Maine has the rocks. California’s Salton Sea geothermal brine is in pilot. The deposits are everywhere. The country we depend on for almost all of our processed lithium is China — which processes 60% of the world’s lithium chemicals, 70% of cobalt, 90% of graphite, and 98%of LFP cathodes, despite mining only 25%of the world’s lithium ore. This is the supply-chain story under everything — EVs, drones, AI data centers, grid storage, missile guidance. And it’s the story the United States has finally, belatedly, started to do something about.
- 40MT LiMcDermitt Caldera (NV / OR) — high estimate · world's largest known deposit
- 0.9MT Li₂ONorthern Appalachians (NH / Maine) — USGS Wintzer et al. (April 30, 2026)
- ~44×scale gapCaldera high estimate vs. NH/Maine recoverable median
- 60%China shareof global lithium refining capacity · 98% of LFP cathodes
The McDermitt Caldera is a 28-by-22-mile volcanic depression that straddles the Nevada-Oregon border, formed when a supervolcano erupted roughly 16.4 million years ago and collapsed into itself. Most calderas are interesting to geologists. This one happens to be the largest known concentration of lithium on Earth.
The mechanism is unusual. After the supervolcano collapsed, the caldera filled with a long-lived crater lake. Lithium-bearing volcanic ash and groundwater chemistry concentrated lithium into illite-rich claystones — not the brine pools of Chile’s Atacama Desert, not the hard-rock pegmatites of Australia’s Greenbushes, but a clay-bound deposit found nowhere else at this scale. The Science Advances paper that characterized the geology in 2023 (Castor et al.) put the in-situ tonnage at 20 to 40 million metric tons of contained lithium, with a theoretical maximum near 120 MT.
Whole caldera, in-situ: 20–40 MT of contained lithium (Castor et al., Science Advances, 2023).
Thacker Pass project specifically: 3.0 MT of measured/indicated lithium under JORC standards — the southern lobe of the caldera, where Lithium Americas is mining.
Jindalee’s adjacent McDermitt project: 21.5 MT of lithium carbonate equivalent (LCE) in declared resource — the Oregon side of the caldera, 35 km from Thacker Pass.
For context: the Bechtel project page calls Thacker Pass “the largest measured lithium reserve and resource in the world.” That’s the LAC project alone, not the whole caldera.
On April 30, 2026, USGS geologist Niki Wintzer and six co-authors published the first formal quantitative resource assessment of lithium pegmatite deposits in the northern Appalachian orogen — the granite-and-mica belt that runs from western Maine through New Hampshire into eastern Canada. The headline number, after applying an economic filter to convert estimated in-situ lithium to recoverable Li₂O: roughly 900,000 metric tons.
“900,000 metric tons of Li₂O is enough to provide the current annual U.S. lithium supply deficit for 127 years at 2025 rates of apparent consumption.”
USGS — accompanying news release · April 30, 2026
The deposit is locked in granite-family pegmatites— coarse-grained intrusive rock that crystallized slowly enough to trap valuable elements. New Hampshire is, in fact, named after this rock; the “Granite State” license-plate motto is now also a critical-minerals story. Maine’s pegmatite belt has been studied for over a century; the Mt. Mica mine in Oxford County produced gem tourmaline starting in 1820. Lithium has been visible in samples for decades. What was missing was a systematic resource estimate. The Wintzer team built one using geologic maps, geochemical sampling, and global-analog simulation.
The southern Appalachian companion assessment puts an additional 1.43 MT of Li₂O in the Carolinas — concentrated near the historic Kings Mountain district that produced the first large-scale U.S. lithium-pegmatite mining. Albemarle and Piedmont Lithium are both back in that area in 2026. The northern Appalachian deposits, by contrast, have no active or planned mines. They are at square one.
Two deposits, two completely different rock types. The economics, the mining method, the environmental footprint, and the time-to-first-pound all hinge on this distinction.
McDermitt (illite-rich claystone): soft, near-surface, can be mined with conventional open-pit equipment. The lithium is liberated by sulfuric-acid leach at the processing plant. Permits are easier than for hard-rock mines, energy intensity is lower per pound of lithium, and the deposit is shallow enough that overburden ratios are favorable.
Northern Appalachians (hard-rock pegmatite): tough granite-family rock. Mining requires drilling, blasting, and heavy crushing. Lithium minerals (spodumene, lepidolite, petalite) must be liberated by high-temperature roasting before chemical conversion. Capex per pound is higher; permitting timelines are longer, especially in heavily forested, water-sensitive states like New Hampshire and Maine.
Translation: the Nevada deposit is bigger AND cheaper to extract per ton. The Appalachian deposit is real, but it’s a 10-to-15-year buildout under the most permissive permitting scenario. The two are not interchangeable in any near-term policy timeline.
Thacker Pass sits at the southern lobe of the McDermitt Caldera, about 60 miles northwest of Winnemucca in Humboldt County, Nevada. The project is a joint venture between Lithium Americas Corp. (LAC) — 62% — and General Motors Holdings LLC — 38%. GM has committed up to $945 millionacross two tranches, becoming the largest GM-direct upstream raw-materials investment in the company’s history and securing exclusive offtake of Phase 1 production.
Bechtel is the general contractor; the Department of Energy’s Loan Programs Office issued a $2.26 billion conditional loan in October 2024. Construction broke ground in 2023, ran through Phase 1 site preparation in 2024-2025, and as of March 26, 2026 had roughly 1,000 workers on site. Peak workforce is projected at 1,800 later this year.
The federal government’s posture changed materially in late 2025. After negotiations between the Trump administration’s DOE and Lithium Americas, the loan was restructured on October 1, 2025. The new terms gave the U.S. Government a 5% equity ownership in Lithium Americas (via warrants) and an additional 5% ownership in the LAC/GM joint venture (also via warrants). The official DOE rationale: protect taxpayers, ensure the project goes forward, secure access to the largest confirmed lithium deposit in North America. The political read: the Trump administration is willing to take direct equity in domestic critical-mineral projects to break Chinese supply-chain leverage. This is unusual American industrial policy.
“The U.S. Government's stake in the project delivers on President Trump's agenda to better steward taxpayer dollars, and ensures the project will go forward, spurring the creation of manufacturing jobs and securing our nation's access to the largest confirmed lithium deposit in North America.”
U.S. Department of Energy · October 1, 2025
Phase 1 capacity: 40,000 metric tons per year of battery-grade lithium carbonate.
Mechanical completion target: late 2027.
Full Phase 1 ramp-up: through 2028.
Phase 2: additional 40,000 t/y, targeted commercial production from 2028-2029.
GM offtake: up to 100% of Phase 1; up to 38% of Phase 2 with option to expand.
U.S. lithium output benchmark: Phase 1 alone would produce more than 8× current total domestic lithium output, per Bechtel's project page.
Two years of slippage from the originally announced “late 2026” production target reflect what is, by industrial standards, a normal lithium-clay project pace. The leach circuit chemistry is genuinely novel; the Trump-era policy environment is friendlier to permits and federal financing than the Biden-era environment was, but it is not magic. The clock starts when the plant takes its first feed.
New Hampshire and Maine have no active lithium mines. No company has filed a Notice of Intent on a major new pegmatite operation. There is no environmental impact statement underway, no federal loan request pending. The USGS report is a resource assessment— meaning it tells you how much is probably there, not how much can be economically extracted under any specific permitting regime.
What changes the calculus: the Maine Geological Survey and New Hampshire Department of Environmental Servicesnow have a federal-grade tonnage number to work with. Land-use planners, town selectboards, and tribal-consultation processes can begin without speculation. If a mining operator were to begin permitting today, — against a hard-rock-mining permit timeline that runs 8-12 years in cooperative jurisdictions — first lithium production from the northern Appalachians would land roughly 2034 to 2038. By that time, the McDermitt build-out will be in Phase 3 or beyond.
McDermitt is the heavyweight, the Northern Appalachians are the newcomer, but the U.S. lithium story spans at least eight states with active or near-term projects. Counting them all, America’s aggregate lithium resource sits around 19 million metric tons— third in the world behind Bolivia and Argentina.
Nevada (clay + brine): McDermitt Caldera (Lithium Americas / GM, 20-40 MT in the broader caldera) and the Clayton Valley brine operation run by Albemarle — the only active U.S. lithium producer for decades.
North Carolina (hard-rock pegmatite): Kings Mountain (Albemarle, restart underway), Piedmont Lithium’s Carolina Lithium project, plus the broader Carolina Tin-Spodumene belt. Southern Appalachian USGS estimate: 1.43 MT of recoverable Li₂O.
South Carolina (hard-rock pegmatite): shared with NC; Kings Mountain district extends across the state line.
Maine and New Hampshire (hard-rock pegmatite): 900,000 MT of recoverable Li₂O per the April 30, 2026 USGS assessment. No active or planned mines.
California (geothermal brine): the Salton Sea Known Geothermal Resource Area — estimates run from 4 to 18 MT of contained lithium dissolved in the geothermal brine. EnergySource Minerals, Berkshire Hathaway Energy, and Controlled Thermal Resources all have direct-lithium-extraction (DLE) pilots running.
Arkansas (Smackover Formation brine): Standard Lithium and ExxonMobil are both piloting DLE; Exxon announced commercial lithium production targeted by 2027. Resource estimate: 5-19 MT in the broader Smackover.
Utah (Paradox Basin brine): Anson Resources advancing pilot operations in southeast Utah.
Wyoming (Rock Springs Formation): Earlier-stage exploration; American Lithium Minerals and others.
Add the McDermitt headline number to all of the above and the United States has more than enough lithium in the ground to meet domestic demand for the rest of the century. The bottleneck has never been geology. It’s permitting, capital, and refining capacity.
The reason any of this matters — the reason a clay deposit in northern Nevada justifies a $2.26 billion federal loan and a direct government equity stake, the reason the USGS spent two years writing a 200-page assessment of the Granite State’s rocks — is that the United States today does not control its own battery supply chain. China does. And it has built that control deliberately, over twenty years, with state policy and patient capital.
China mines roughly 25% of the world’s lithium — a number that sounds modest. The control is in the next stage. China refines roughly 60% of global lithium chemicals. It refines 70% of cobalt. It refines 90% of graphite, the active material in every battery anode in commercial production. It manufactures 85% of the world’s battery cells by monetary value. And in the lithium-iron-phosphate (LFP) cathode chemistry that has come to dominate the EV and stationary-storage markets, Chinese firms hold over 98% of global production capacity. CATL alone is roughly 38% of global cell production. BYD adds another 17%.
Mining: stand up domestic deposits at scale — Thacker Pass, Lithium Americas’ Pastos Grandes (Argentina, partner project), Albemarle’s Kings Mountain restart, Piedmont’s Carolina Lithium project. The Appalachian USGS data add roughly 2.3 MT of recoverable Li₂O to the U.S. resource base.
Refining: the bottleneck. The U.S. has very few lithium-conversion plants; LAC’s Phase 1 plant at Thacker Pass is one of the largest under construction in the Western Hemisphere. DOE Loan Programs Office, the Defense Production Act ($1B through September 2027), and IRA §30D source-of-origin rules are the three policy levers.
Cathode and cell: Ford and GM are building battery plants in Tennessee, Kentucky, and Michigan; Tesla’s Nevada Gigafactory is expanding LFP cell capacity. Korean partners (LG Energy Solution, Samsung SDI, SK On) are filling the gap left by Chinese vendors. Domestic LFP cathode production remains tiny.
Total time horizon: 2028-2032 to reach 50% of U.S. battery demand from non-Chinese refining and cell capacity, on the most optimistic build-out trajectory. McDermitt is the lithium half of that equation.
The United States is sitting on roughly 19 million metric tons of lithium — third in the world, eight states deep, ranging from a Nevada supervolcano to Maine pegmatite to a California geothermal field to an Arkansas oilfield brine. Geology is not the problem. Refining is. China processes 60% of the world’s lithium chemicals and 98%of LFP cathodes today. America’s next ten years — under whichever administration — will be measured by whether we built the furnaces, leach circuits, and cathode plants here, or whether we shipped a strategic resource overseas to be processed by a competitor and shipped back as finished battery cells. McDermitt is the proof of concept. New Hampshire is the proof the resource is bigger than anyone realized. The federal government just took a 10% equity stake in the first leg of the bet. The rest is the harder part.