Lovecraft circle Seal Devil Reef is an offshore rock formation located a mile and a half out to the sea near Innsmouth, Massachusetts. Most of the time it jutts out of the sea and is only thinly covered at high tide. Rumours abound that the rocks are home to a legion of devils and imps or a hidden pirate hoard. While the day brought constant swimming races to the reef, at night fully fledged Deep Ones would move back and forth between the rocks and the town.


The reef was used by Captain Obed Marsh as a meeting point when contacting the Deep Ones of Y’ha-nthlei from around 1838.

In 1846, after a sacrificial ritual at the reef, Captain Marsh and several members of the Esoteric Order of Dagon were arrested by Selectman Mowry. No formal charges were made as Mowbry and his supporters were soon killed during the Innsmouth riots.


Beyond the reef the water decends into an immeasurably deep trench known as Y'ha-nthlei, home of the Deep Ones. 

It was torpedoed during the government raid of 1928 but not destroyed.

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