Grandcamp-Maisy (French pronunciation: [ɡʁɑ̃kɑ̃ mɛzi] ⓘ) is a commune in the Calvados department in the Normandy region in northwestern France.

From his research and released (previously top secret) papers, the site is many times larger than was originally thought.

It contains office bunkers, supplies buildings, general quarters, radio rooms, and many other blocks, including an underground hospital (one of three which has been uncovered and can be visited).

On the morning of 6 June 1944, HMS Hawkins claimed to have put the guns out of action, but Maisy was hit with shells for a further three days by many navy ships.

Hawkins also claimed to have put the battery at St Martin de Varreville out of action, but it is a well-known fact[citation needed] that the guns were not there on the morning of D-Day and had been moved further inland.