MassDEP's Central Regional Office serves the region that spans from the Connecticut border to the New Hampshire line and encompasses all of Worcester county. It also includes some municipalities in western Middlesex and Norfolk counties. In all, there are 77 towns and cities with a total population of nearly 900,000.
MassDEP's Northeast Regional Office serves 84 cities and towns situated in northeastern Massachusetts. The region spans from the New Hampshire border south through metropolitan Boston to Quincy and is bounded on the west by a line that extends roughly from Ashland to Westford.
MassDEP's Southeast Regional Office serves 84 towns and cities and the major islands of Martha's Vineyard, Nantucket and the Elizabeth chain. It stretches from the southern suburbs of Boston to the Rhode Island border to Cape Cod.