The Kelvedon Hatch Secret Nuclear Bunker at Kelvedon Hatch, in the Borough of Brentwood in the English county of Essex, is a large underground bunker maintained during the Cold War as a potential regional government headquarters. Since being decommissioned in 1992, the bunker has been open to the public as a tourist attraction, with a museum focusing on its Cold War history.

Kelvedon Hatch is a village and civil parish in the Borough of Brentwood in south Essex, England. It is situated just north of Pilgrims Hatch, approximately 4 miles (6.4 km) to the north of Brentwood and is surrounded by Metropolitan Green Belt. In 2019 the built up area had an estimated population of 2,434. The parish had a population of 2,563 in 2001, reducing to 2,541 at the 2011 Census and climbed back up to 2,631 in 2021.