Innsmouth is the city in Massachusetts. It was built on the coast of the Essex county. The river Manuxet flows through the centre of the city. Most of the game plot is centered in Innsmouth.
The city was founded in 1643. In those days, it was known for shipbuilding, fishing and trade. The city was doing pretty well until 1815. The fish left the waters, and trade disappeared. Obed Marsh was the wealthiest man in the city and he had three ships: Columbia, the Hetty, and the Sumatra Queen. He often went on long voyages to the Pacific Ocean where he traded with the local natives. His trade was saving the city for a long time. He met chief Walakea who taught him how to summon the Deep Ones; ancient creatures that dwell in the ocean. After he came one day to the islands, he could not find any trace of the natives. So when he returned to Innsmouth, in fear of impoverishment, he went to Devil's Reef and talked to Deep Ones. Soon Obed and some of his sailors started worshiping them. Obed bought the old Masonic tample and founded the Esoteric Order of Dagon. In 1846 the christian citizens rebelled and captured Obed and his followers. Soon the Deep Ones came to aid Obed and they killed everyone on their way. Those who survived the slaughter were forced to take the Oaths of Dagon. These were the Oath of loyalty, secrecy and of the Oath of mating with a Deep One. This lead to the skin disease known as the ''Insmouth Look''. The city was destroyed in the U. S. attack of 1922.