Mary Costigan Mary Costigan

Mary Costigan


Meet Mary, public sector powerhouse turned permitting pro.

Mary Costigan


207 228-7147 direct
207 774-1200 main
207 774-1127 facsimile

100 Middle Street
PO Box 9729
Portland, ME 04104-5029

  • The Best Lawyers in America® 2024
    Environmental Law
    Land Use and Zoning Law
    Municipal Law

Here’s why you’ll enjoy working with her.

Calm under pressure, dependable, and a true advocate for her clients, Mary is an experienced municipal and environmental law counselor. Having worked in the public sector for years before joining Bernstein Shur, she has a firsthand understanding of the issues faced by municipal and state employees and boards—and how to help her clients confront them. Her most recent public sector position was associate corporation counsel to the City of Portland, where she advised the city staff and council on waterfront redevelopment and rezoning, among other projects, and was a resource for numerous committees—Energy and Environmental Sustainability and Community Development Committees, to name a few. Outside of the office, she teaches a Municipal Law Course at the University of Maine School of Law.


But that’s not all. Mary is also very experienced in:

  • The ins and outs of land use permitting, including subdivision and site plan review
  • Zoning compliance, zoning amendments, and conditional rezoning
  • Representation before local and state boards, such as planning boards, zoning boards, town councils, and the Maine Board of Environmental Protection
  • General municipal law
  • Administrative and judicial appeals
  • Enforcement actions
  • Wind power development
  • Stormwater management
  • Natural resource protection

In her former life, Mary was:

  • Associate corporation counsel for the City of Portland
  • President of the Long Creek Watershed Management District Board, where she helped implement the stormwater management plan for Long Creek
  • Aquaculture administrator and hearing officer for the Maine Department of Marine Resources responsible for adjudicating the leasing of submerged lands for aquaculture facilities
  • Assistant attorney general in New Jersey, where she focused on air quality permitting
  • Clerk in the New Jersey Superior Court

When Mary isn’t working, she is…

Running a marathon, in and outside of the United States. Mary’s also a big Bruce Springsteen fan and can often be found enjoying live music.


JD, Vermont Law School, 1997
MS, Vermont Law School, 1997 BA, University of Delaware, 1994

Admitted to practice
State of Maine
US District Court, District of Maine


Maine State Bar Association
Portland Community Chamber of Commerce, Vice President