Lake Attitash is a lake located on the border of Merrimac, Massachusetts and Amesbury, Massachusetts, and constitutes at least a portion of Amesbury's water supply. There are beaches on both the Amesbury and Merrimac shores. Merrimac's beach is known as Indian Head Park. The lake was formerly known as "Kimball's Pond." Its name was changed …Lake Attitash is a lake located on the border of Merrimac, Massachusetts and Amesbury, Massachusetts, and constitutes at least a portion of Amesbury's water supply. There are beaches on both the Amesbury and Merrimac shores. Merrimac's beach is known as Indian Head Park. The lake was formerly known as "Kimball's Pond." Its name was changed to reflect its reputed indigenous name of Attitash, meaning huckleberry.