On the night of March 21, 2026, Elon Musk took to X to formally announce “the TERAFAB project” — a joint venture of Tesla and SpaceX, with xAI (which SpaceX absorbed earlier this year) in the mix and Intel signing on as a manufacturing partner that April. Terafab is a semiconductor fabrication plant built around one staggeringly large number: one terawatt — 1,000 gigawatts — of new AI compute capacity produced per year. No fab in history has ever been asked to deliver that, and that’s precisely the point. Musk has called it “the most valuable building on Earth by far.”
How big is it?
The plan calls for more than 100 million square feet of factory floor. Tesla’s Gigafactory Texas — already one of the largest buildings on Earth — holds roughly 10 million square feet, so Terafab is designed to be about ten times bigger. Fortune, which reviewed the project filings, notes the footprint would be roughly five times larger than the biggest building standing anywhere today. The project’s own comparisons: larger than the Pentagon, Apple Park, and the Mall of America combined — or, if you prefer geography to architecture, roughly the size of Vatican City, Monaco, and Gibraltar rolled into one, all under a single roof.
Phase one is reported at about $16.8 billion, on a site in Grimes County, Texas, between Austin and Houston. County tax-incentive filings put construction starting December 1, 2026, with completion targeted for the end of 2028 and incentives running through 2038 — with performance bonds posted to the local Anderson-Shiro and Iola school districts as a guarantee the company actually delivers. Early reports peg initial staffing around 3,000 jobs, and Governor Greg Abbott has touted it as a first-of-its-kind facility for American chipmaking...
