Throughout the series the towns Derry and Castle Rock are mentioned on several occasions. Both towns are fictional and are often used by Stephen King in his novels and short stories. "It", "Bag of Bones" and "Dreamcatcher" take place, a least in part, in Derry. "Needful Things", "The Dark Half", "Cujo" and "The Dead Zone" are among the stories that take place in Castle Rock.
Along with Jerusalem's Lot (Salem's Lot), Derry and Castle Rock form a trinity of fictional towns King often uses as a setting for his stories, they are all placed in Maine. The trinity is an homage to 'H. P. Lovecraft''s trinity of Arkham, Innsmouth and Dunwich.
The show "Haven" is loosely based on Stephen King's "Colorado Kid", which in turn is loosely based on a real-life murder that took place in Australia in the late 1940s, the case of the Somerton Man. The mystery involves genetic anomalies, several copies of a rare book, death by digitalis, and spies.
The opening credits mention "The most Revered Flagg". Randall Flagg is a prominent character in many of Stephen King's stories. He can be thought of as King's "ultimate villain/bad guy".
The Stephen King novel "The Tommyknockers" also took place in Haven. Stephen King wrote "The Colorado Kid" which "Haven" is inspired by.
In episode 10 of Season 4 'The Trouble with the Troubles' a take-out flyer is seen with the name 'Captain Trip's Cafe'. Captain Trip's was the name given to the plague in Stephen King's book The Stand.