About Mahon, Mahon, Kerins & O'Brien, LLC
Mahon, Mahon, Kerins & O'Brien, LLC is a law firm based in Garden City South, New York, whose official website centers on estate and trust work. The site says the firm has a long history of guiding clients through the duties of administering an estate or trust. It also includes a page on counsel work for the Nassau County Public Administrator, a public fiduciary office, and describes the firm's involvement in cases where the Public Administrator serves as fiduciary.
The firm lists practice areas including estate planning, probate and intestate administration, estate and trust litigation, elder law and Medicaid planning, wrongful death proceedings, personal injury, civil and commercial litigation, employment law, and real estate. Its website states that it serves clients across New York City and Long Island, specifically Suffolk and Nassau counties. The only office address published in the sources reviewed is 254 Nassau Boulevard, Garden City South, New York 11530.
| Type | Law firm |
|---|---|
| New York offices | Garden City South |
| Phone | (516) 538-1111 |
| Website | mmkolaw.com |
| Registered NY attorneys | 7 |
Practice areas
Areas of work that Mahon, Mahon, Kerins & O'Brien, LLC describes on its own website. They describe the organization as a whole, not the practice of any individual attorney listed below.
Organization profile based on its official website and public sources (reviewed October 30, 2026). Attorney list from the New York State Unified Court System registration data. Not affiliated with Mahon, Mahon, Kerins & O'Brien, LLC.
Registered attorneys
Lawrence Mahon Currently registered Richard Kerins Currently registered Robert O'Brien Currently registered Joseph Hyland Currently registered James Kerins Currently registered Shannon O'Brien Currently registered Heather Callaghan Currently registeredRegistration status can change at any time. Confirm any attorney's current status through the official New York Attorney Search.