Mary Susan Leahy
Of Counsel, Trusts & Estates Department
100 Arboretum Drive
Suite 140
Newington, NH 03801

Mary Susan is a versatile estate planning and trust attorney. In addition to advising on personal estate and tax planning issues, she also advises clients on business succession planning, having spent many years as a transactional business lawyer. Drawing on her experience as a real estate attorney, she counsels families on generational planning, such as involving ownership of lakefront and other vacation properties. She serves as a professional trustee of many private trusts and counsels charitable foundations and other tax exempt organizations.

Susan received her J.D. from Boston University School of Law.

Areas of Focus

  • Corporate Business Law
  • Estate Planning and Trust and Estate Administration
  • Probate Litigation
  • Taxation


  • New Hampshire State Courts
  • Maine State Courts
  • United States Supreme Court
  • United States First Circuit Court of Appeals
  • Federal District Court for the District of New Hampshire
  • United States Tax Court
  • Fellow of the American College of Trust and Estate Counsel (ACTEC)


  • New Hampshire Bar Association and its Sections of Elder Law and Real Property and Probate
  • Maine Bar Association, American Bar Association and its Sections of Taxation and Real Property and Probate
  • New Hampshire Women’s Bar Association
  • Constitutionally Speaking, Treasurer
  • New Hampshire Institute for Civics Education, Founder and Chair
  • Kennebunkport Conservation Trust, Trustee
  • Dartmouth Hitchcock’s Partners for Community Wellness, Executive Committee Member



  • Best Lawyers in America (Corporate Law, Trusts & Estates Law), 1997 – present
  • New Hampshire Women’s Bar Association’s Marilla M. Ricker Achievement Award
  • Greater Concord Chamber of Commerce Citizen of the Year Award
  • Merrimack County Bar Association Lawyer of the Year Award
  • New Hampshire’s Most Powerful Women Award