National Marine Sanctuary: Stellwagen Bank
Between Cape Ann and Cape Cod, in the southwest corner of the Gulf of Maine, is Massachusetts Bay. The bay's most prominent submerged feature is the kidney-shaped plateau called Stellwagen Bank, which lies at the bay's eastern edge. Stellwagen Bank is a shallow, primarily sandy feature, curving in a southeast to northwest direction for 19 miles. It is roughly 6 miles across at its widest point at the southern end. Water depths over and around the bank range from 65 feet on the southwest corner to depths of about 600 feet in deep passages to the northeast. Massachusetts Basin on the western side of the sanctuary levels off at about 300 feet in depth, while the top of the bank averages about 100 to 120 feet.
Stellwagen Bank is the centerpiece of the Stellwagen Bank National Marine Sanctuary, which encompasses a total of 638 square nautical miles, or 842 square miles. The sanctuary also includes all of Tillies Bank (situated to the northeast of Stellwagen Bank) and southern portions of Jeffreys Ledge (situated to the north). The western boundary line of the sanctuary is approximately 25 miles east of Boston; the southern boundary is three miles from Provincetown while the northwestern boundary is three miles from Gloucester. From the sanctuary's Scituate-based headquarters, the distance is approximately 11 miles.