An Area of Critical Environmental Concern (ACEC) boundary is delineated upon designation by the Secretary of Energy and Environmental Affairs and includes the area needed to protect and preserve significant natural resource features such as estuaries, wetlands, floodplain, and forested upland. For each ACEC there are two helpful products:

  1. a map showing the boundary line – typically illustrated on a United States Geological Service (USGS) topographic base map, and
  2. text describing how the boundary was defined upon designation.

Historically, the boundary map has been used for general land use planning and resource management applications, while the boundary text is used for regulatory interpretation and site-specific project reviews. The ACEC boundary is important because it identifies an area in which to focus stewardship activities, resource management, and heightened environmental review of certain proposed projects.  All boundary descriptions are available online in the individual ACEC designation documents linked on each ACEC web page.

There are a number of ways to view ACEC boundaries. We have an ACEC statewide map pdf format of    Massachusetts Areas of Critical Environmental Concern  available online that shows all designated ACECs. Individual ACEC boundary maps are available as hard copy from the ACEC Program . Large format color printed theme maps are also available to order at a cost from MassGIS.

ACEC boundaries can also be viewed through several online map tools.  For mapping professionals, a digital data layer of ACEC boundaries is available for free downloading at the MassGIS website . Also, an interactive online data viewer, called OLIVER, is available via MassGIS. With OLIVER you can choose to view many different data layers for reviewing an area.  Or you can go to separate browser-based mapping applications on different topics that use pre-selected backgrounds, including an ACEC-specific one. See our directions for this boundary viewer entitled ‘ACEC Boundary Viewer Directions’ on the right side of this page.

ACEC Online Maps

On each ACEC web page we have linked online maps showing individual ACEC boundaries from two perspectives - as the entire ACEC boundary (ACEC Index Map) and from zoomed in close-ups (ACEC Map Tiles).  For general information, view the Index Map of an ACEC with the ACEC boundary shown on one page with roadways and municipal boundaries. For more detailed information, use the Map Tiles which show 1:24,000 USGS Topographic Quad maps with ACEC boundaries superimposed. Map Tiles show a portion of the ACEC at a time (depending on the size of the ACEC).

The ACEC Index Maps are also used to choose a specific area of the ACEC to view in more detail (Map Tile).  Choose a region to view from the ACEC Index Map and remember the associated Map Tile number as indicated (e.g., 9c).  Return to the ACEC web page and click on the Map Tile you want to see in detail.

To access these new maps, go to the desired ACEC web page and look under the ‘Maps’ section in the right column of the page. An ACEC Statewide Map pdf format of    Massachusetts Areas of Critical Environmental Concern  summarizes the new ACEC map information and is also available on each ACEC web page. The ACEC Statewide Map shows Massachusetts ACECs with numbered squares depicting the locations of individual ACEC Map Tiles.

Boundary Clarification Project

Some ACECs boundaries have been updated to include coded boundary segments (as part of an ongoing update program) – see Boundary Clarification Project .  Six ACECs on Cape Cod have coded boundary descriptions linked on their web pages and the four most recent ACEC designations also include coded boundary descriptions online.