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About Sullivan Mahoney LLP

From humble beginnings in a two man office, the path to the present has witnessed Sullivan Mahoney emerge as Niagara’s pre-eminent law firm. A firm providing cutting edge legal services through a team of 31 skilled lawyers and 40 legal assistants, law clerks and administrative support staff.

While the names on the doors of the Sullivan Mahoney Law Offices have changed with time, our commitment to our vision and core values endures.

We are committed to maintaining the tradition of excellence established by those before us. We are firm in our resolve to provide strategic and cost effective advice in our vigorous pursuit to protect and add value to client interests.

The success of any law firm begins with its clients. We are grateful for the strong and long lasting relationships with a diverse group of clients and we are most appreciative of the trust and confidence they have always placed in us.

Sullivan Mahoney Our Tradition

Our Tradition

The Firm was founded in 1953 by Philip H. Sullivan and C. Hugh Mahoney, and has established a tradition of integrity, skill and professionalism. 60 years later, we still embrace those values – and they form a solid foundation upon which we’ve grown.

Sullivan Mahoney LLP is the largest law firm in Niagara, providing a full range of legal services to our diverse client base.

We have earned an unsurpassed reputation for impeccable service, thorough and pragmatic legal advice and complete commitment to our clients. Our lawyers are knowledgeable and dedicated to their professional development in order to best serve our clients’ needs.

Not only are we committed to our clients, but also to our communities. We give back through charitable donations, fundraisers and sponsorships.

In the Community

Sullivan Mahoney LLP is a proud supporter of our local communities. We have raised $45,000 for the Heart and Stroke Foundation in the St. Catharines Big Bike event in support of our friend and colleague Peter Banwell.

We have also raised $11,000 for Cancer Research in the Relay for Life, in honour of our late friend and colleague Gord Wiggins.



The Firm supports many local organizations including:
  • Bethlehem Projects
  • Brock University
  • Carousel Players
  • Child Advocacy Centre
  • Cuvee
  • Henley Regatta
  • Hospice Niagara
  • Lyndesfarne Theater Projects
  • Niagara College
  • Niagara Community Foundation
  • Niagara Entrepreneur Awards
  • NHS “It’s Our Time” Campaign
  • Rankin Cancer Run
  • School Board Scholarships
  • Seymour-Hannah Sportsplex
  • Shaw Festival
  • Wellspring Niagara
  • YMCA