Maine Coastal Barrier Resources System

What is a CBRS?

Beaches and dunes often form a sand and gravel landform, or barrier, between the ocean and a coastal wetland. This landform is called a coastal barrier. Commonly referred to as a barrier beach or barrier island, coastal barriers take on many forms. Some undeveloped or lightly-developed coastal barriers are recognized by both federal and Maine state law as dynamic environments that continually change and have been designated as part of the Coastal Barrier Resources System (CBRS). Most of Maine's largest developed beaches are not part of the CBRS; those that qualify for either federal and/or state designation, make up the CBRS in Maine.

How do I view CBRS areas?

Maps showing the geographic extent of the CBRS in Maine are available for viewing by appointment at the Maine Geological Survey (MGS) or can be accessed using the MGS Viewer below. Maps may also be viewed and downloaded from the U.S. Fish and Wildlife Service. The table below the MGS viewer provides a listing of each designated CBRS Unit name, the associated Maine town, Unit number, Unit designation (Federal System Unit, Otherwise Protected Area, and/or Maine System Unit), and any additional important notes.

What activities are limited in CBRS areas?

Because of the highly dynamic nature of these systems, there are certain prohibitions on activities within CBRS areas, especially those that utilize State or Federal funding. Coastal projects should review the location of planned development in relation to the CBRS boundaries and be aware of prohibitions in the laws. For example, Community Development Block Grants that use public funds must determine if a site is within the CBRS as part of their environmental review process. Most new or substantially improved residences, businesses, or other developments in the CBRS are not eligible for certain federal or Maine state funding and financial assistance, including coverage under the federal National Flood Insurance Program (NFIP). Note that CBRS are also mapped as coastal sand dunes by the MGS and activities within these areas may also require additional State permitting.

How can I find out more about CBRS?

The following links have much more detail on the Coastal Barrier Resources System and their management in Maine.

• Maine Coastal Barriers per Maine Statute
• Coastal Barrier Resources Act (U.S. Fish and Wildlife Service)
• Coastal Barrier Resources System (U.S. Fish and Wildlife Service)
• Coastal Barrier Resources System (FEMA)
• Maine Floodplain Management Program
• Maine Coastal Management Policies
• Maine Coastal Sand Dune Maps
• Maine Coastal Sand Dune Rules
• Coastal Barriers in the US - The Encyclopedia of Earth
• CBRS Report, Government Accountability Office, 2007
• CBRS Report on USFWS Mapping, Government Accountability Office, 2021

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Web Map

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Data Download

The CBRS unit polygons for areas defined by Federal and Maine statute can be downloaded as shapefiles for use in any GIS software to perform further spatial analysis.

• Federal CBRS Boundaries
• Maine-defined only CBRS Boundaries
• Unit Lines
• Units

Data Description and Usage

These data are representations of the CBRS boundaries shown on the official CBRS maps referenced in 16 U.S.C. 3503(a). In general, these digital boundaries can be considered accurate to within approximately 20 feet of the actual CBRS boundaries as shown on the official maps. Before using the data, please read the metadata for additional information. Additionally, because CBRS units extend seaward out to either the 20- or 30-foot bathymetric contour (depending on the location of the unit), the true seaward extent of the units is not shown. The Service is not responsible for any misuse or misinterpretation of this digital data set, including use of the data to determine eligibility for federal funding or financial assistance.

Data Disclaimer

The U.S. Fish and Wildlife Service (Service) is not responsible for any misuse or misinterpretation of this digital data set, including use of these boundaries (which are approximate digital representations of the boundaries shown on the official maps) to determine eligibility for Federal expenditures and financial assistance including Federal flood insurance. The official Coastal Barrier Resources System (CBRS) maps (not these digital data) are the controlling documents of the CBRS boundaries and are maintained by the Service.

Official CBRS Maps List

References

Robert R. Kuehn, 1981, The shifting sands of federal barrier islands policy. Harvard Environmental Law Review, v. 5, n. 2, p. 217-258.

Robert R. Kuehn, 1984, The Coastal Barrier Resources Act and the expenditures limitation approach to natural resources conservation: wave of the future or island unto itself? Ecology Law Quarterly, v. 11, n. 4, p. 583-670.

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Last updated on January 28, 2025