No, Little Tall Island is a fictional coastal Maine island, which is the setting of numerous Stephen King stories such as "Storm of the Century" and "Dolores Claiborne".
As a dedicated resident of Maine, author Stephen King found himself enchanted by the State’s rugged coastline. As such, when he wrote the miniseries Storm of the Century, the town of Mount Desert Island was transformed into the fictional Little Tall Island.
Mount Desert Island represented Little Tall Island in the film version of "Pet Sematary." Mount Desert Island is home to the Coach Stop Inn, (coachstopinn.com), said to house the ghost of a little girl who likes to flicker the lights and rearrange people's belongings.
See Haunted Destinations in Maine featured at USA Today.