View of much of the Central Nashua River Valley ACEC from Prospect Hill in Harvard, MA - Photo by Kristopher Kvenvold

Stewarding Special Landscapes: Areas of Critical Environmental Concern

The Nashua River watershed is home to three of the Commonwealth’s twenty-eight Areas of Critical Environmental Concern (ACEC), comprising more than one quarter of all ACEC land in Massachusetts. The Central Nashua River Valley ACEC was designated in 1996 and includes 12,900 acres in the communities of Bolton, Harvard, Lancaster, and Leominster. Details and maps of the Central Nashua River Valley ACEC. The Squannassit and Petapawag ACECs, designated in 2002, are the two largest ACECs to date, with Squannassit covering 37,450 acres and Petapawag covering 25,630 acres in the communities of Ashby, Ayer, Dunstable, Groton, Harvard, Lancaster, Lunenburg, Pepperell, Shirley, Townsend, and Tyngsboro. Details and maps of the Squannassit ACEC; Details and maps of the Petapawag ACEC

An Area of Critical Environmental Concern (ACEC) is a special designation given by the Commonwealth of Massachusetts to a region that has high quality, unique, and significant natural and cultural resources. Nominations for ACEC designation are made at the community level and proceed through a process of compiling nomination papers detailing the area and its valuable assets, public outreach and education, review by the state's Executive Office of Energy and Environmental Affairs (EOEEA), public hearings, and finally, if appropriate, designation by the Secretary. More about the Commonwealth's ACEC program

The NRWA was a key partner in the nomination process for the Squannassit and Petapawag ACECs. The many unique qualities of the region led to their designation. The Squannassit/ Petapawag region contains one of the most remarkable concentrations and varieties of glacial landforms in New England. These landforms contributed to the highly variable nature of soils and complex hydrologic systems within the region. Combined with regional geography, these characteristics resulted in a diversity of habitat types and rich biodiversity. Remarkable concentrations and varieties of wildlife, including rare and endangered and/or threatened plant, animal and fish species, reside in the Squannassit/Petapawag region. Both ACECs contain eighteenth and nineteenth century structures and landscapes which provide significant historical resources. In addition, both Squannassit and Petapawag ACECs contain extensive conservation lands and recreation areas.

The NRWA facilitates a Stewardship Committee of local citizens that focuses on expanding public outreach and education on significant stewardship topics as they emerge. The Committee played an important role in launching an NRWA project to raise galerucella beetles for release to control invasive purple loosestrife. 

For more information about the Areas of Critical Environmental Concern, please contact Al Futterman, NRWA Land Programs Director, at (978) 448-0299, or This email address is being protected from spambots. You need JavaScript enabled to view it. .