Sullivan Mahoney LLP
Automatically compiled listing. Details may contain errors.32 lawyers · Established 1953 · Niagara Region
One of 61 law firms listed in St. Catharines, and one of 3 handling Administrative & Regulatory Law.
About Sullivan Mahoney LLP
Sullivan Mahoney LLP is a full service law firm based in St. Catharines, Ontario, with a second office in Niagara Falls. Philip H. Sullivan and C. Hugh Mahoney sealed their partnership with a handshake in 1953, starting the practice in a three person office. More than 70 years later it has grown into one of the larger firms in the Niagara region, with more than 30 lawyers working across 12 practice groups: administrative law, business law, civil litigation and advocacy, construction law, criminal law, employment and labour law, estates, wills and trusts, family law, municipal and land use law, personal injury law, real estate law, and tax law.
The firm served as legal counsel to the 2022 Canada Summer Games, hosted in the Niagara region that August. A partner at the firm chairs the Niagara Escarpment Commission, the Ontario government agency that reviews development along the Niagara Escarpment, a UNESCO World Biosphere spanning 725 kilometres. Another partner was included in the 2025 edition of The Best Lawyers in Canada for labour and employment law, and in 2021 Sullivan Mahoney was among the firms nominated in the Canadian Law Awards' Ontario regional firm category.
Practice areas
Administrative & Regulatory Law
Business & Corporate Law
Civil Litigation & Dispute Resolution
Construction Law
Criminal Defence
Employment & Labour Law
Wills, Estates & Trusts
Family Law
Real Estate Law
Tax Law
Our guide: Probate in Niagara: An Executor's Guide
Our guide: How to Get a Divorce in Ontario
In the community
- A partner at the firm chairs the Niagara Escarpment Commission, the Ontario government agency that reviews development along the Niagara Escarpment, a UNESCO World Biosphere spanning 725 kilometres.
- Sullivan Mahoney runs a formal community giving program, supporting registered charities and not for profit organizations based in the Niagara region through corporate donations and sponsorships.
- The firm served as legal counsel to the 2022 Canada Summer Games, hosted in the Niagara region that August.
Good to know
Wheelchair accessible
By appointmentLawyers 32
Adam Patchet
Partner
Civil Litigation & Dispute Resolution
Amber N. Harwood
Associate
Business & Corporate LawWills, Estates & Trusts
Andrea M. Mannell
Junior Partner
Administrative & Regulatory LawCivil Litigation & Dispute Resolution
Bradley J. Troup
Managing Partner
Employment & Labour Law
Bruce A. Macdonald
Partner
Criminal DefenceFamily Law
Carly White
Associate
Civil Litigation & Dispute ResolutionFamily Law
Carmelina D'Angelo
Partner
Wills, Estates & TrustsTax Law
D. Andrew Maloney
Partner
Real Estate Law
Danielle Thomas
Associate
Civil Litigation & Dispute Resolution
David M. Willer
Partner
Business & Corporate LawReal Estate Law
Diana M. Continenza
Partner
Family LawPersonal Injury
Erica L. Bush
Junior Partner
Business & Corporate LawWills, Estates & Trusts
Gabriel Costantini
Associate
Italia M. Gilberti
Partner
Business & Corporate LawReal Estate Law
J. Patrick Maloney
Partner
Lana T. Sgambelluri
Partner
Business & Corporate LawWills, Estates & Trusts
Lesley K. Parsons
Partner
Personal Injury
Michael J. Bonomi
Senior Counsel
Employment & Labour Law
Patrick A. Bush
Partner
Business & Corporate LawWills, Estates & Trusts
Patrick J. Lyons
Associate
Peter A. Mahoney
Partner
Richard C. Corbett
Partner
Civil Litigation & Dispute ResolutionFamily Law
Rocco Vacca
Partner
Administrative & Regulatory LawBusiness & Corporate Law
Sam Greenlaw
Associate
Employment & Labour LawCivil Litigation & Dispute Resolution
This firm’s lawyers at a glance
- Called to the bar
- 1972–2024 · median 20 years in practice 30 of 32 lawyers
- Law schools
- University of Windsor (6), University of Western Ontario (5), Queen's University (4), University of Ottawa (3), University of Saskatchewan (2), Dalhousie University and 9 more 30 of 32 lawyers
- Languages on the roster
- English, French, Italian
Who handles what
Offices 2
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Personal InjuryReal Estate LawWills, Estates & TrustsBusiness & Corporate LawThis listing was generated by AI from public sources in September 2026. It may contain errors, and we can’t guarantee it’s accurate or complete. Before you rely on anything here, verify it on the firm’s own website. Verify licence status in the Law Society of Ontario directory ↗
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