Pickaxe Mountain in Iran is one of the most secretive and heavily fortified sites in the country’s nuclear programme and came to prominence after US President Donald Trump threatened to strike it.
Around 1,600 metres above sea level, it is just 1.6km south of Natanz, a key node in Iran’s nuclear network. Although Iran denies any nuclear activity there, years of satellite imagery show an expanding network of tunnels being excavated deep beneath the mountain. Beyond what can be seen from space, details are scarce. Iran has never allowed the International Atomic Energy Agency (IAEA) to inspect the site.
Analysts at the Institute for Science and International Security (ISIS) have tried to reconstruct the underground complex by comparing years of satellite imagery, analysing terrain, measuring excavation spoil, tracking tunnel alignments, and monitoring construction activity. Their assessment indicates four tunnel portals leading to interconnected chambers buried 80-100 metres beneath solid rock, deeper than Iran’s Fordow enrichment plant. The institute’s drawings are estimates, not confirmed designs.
Satellite imagery from 2025-26 indicates construction has continued despite US and Israeli strikes on other Iranian nuclear facilities. According to ISIS, Iran has reinforced tunnel entrances with additional concrete, enlarged protective headwalls, strengthened security perimeters, expanded access roads, and partially sealed some portals while excavation continued behind them.
The Wall Street Journal, citing Israeli and US officials, reported that Iran transferred thousands of centrifuges into the mountain after the June 2025 airstrikes damaged facilities at Natanz, Fordow, and Isfahan. Reuters notes that neither the IAEA nor independent experts have verified that claim. If confirmed, it would strengthen Iran’s ability to rebuild its uranium enrichment programme.
Will the US strike Pickaxe Mountain? The IAEA warns that attacks on nuclear facilities can cause localised radiological and chemical contamination if nuclear material is present. Military analysts think its chambers could lie beyond America’s GBU-57 Massive Ordnance Penetrator, which can work its way down to around 60 metres, depending on the geology. Other options include striking tunnel entrances, penetrating munitions through access portals or ventilation shafts, sabotage, or even a ground assault, but none are considered straightforward.
