Massachusetts is a state in the New England. Mystery Inc., and select other members, have been there several times.
The Scooby-Doo Show
The gang were off to visit a friend, Arlene Wilcox, on Halloween night, in the town of Salem which was being haunted by a witch. The town suspected Arlene and set out to get a confession from her.
The New Scooby and Scrappy Doo Show
The ghost of Shaggy Rogers's relative tried to disrupt the wedding of Shaggy's sister, Maggie.
The 13 Ghosts of Scooby-Doo
One of the "13 Ghost" cases took the gang to Salem.
Scooby-Doo and the Witch's Ghost
They investigated the case of a ghost witch in Oakhaven.
Scooby Doo... Mystery Comics
The gang investigated a Colony Creature in New Lichfield.