In 1998 Bob joined Francis Fleetwood and James McMullan as partners to form Fleetwood, Lenahan and McMullan LLC Architects, a firm based in East Hampton, New York.

His design philosophy draws upon classic and indigenous styles, blending modern ideas and technology. He upholds the highest standards in quality and style for custom homes and renovations in New England as well as the Hamptons.

Robert A. Lenahan Architect is well known locally and praised nationally for his designs. He has been published in various periodicals including Architectural Digest, Elle Décor, House & Garden, House Beautiful, Bon Appe'tit and Classic Home.

Having 26 years of experience in Architecture and Interior Design and privileged to help create over 200 beautiful homes for many wonderful clients, Bob believes that the key to the finest projects is a close collaboration between the client and their Architect.Each house is exhaustingly detailed and designed with the lifestyle and wishes of the client in mind before its creation. The main goal has always been to combine modern living within a traditional design.

In Fall of 2007, Bob and his wife Jeannie, a native of New Hampshire moved their family to Jeannie's hometown of Portsmouth, NH. Bob remained a partner in the Fleetwood,Lenahan and McMullan firm through 2008 and in July 2009 Bob established his own Architecture and Interior Design firm based in the Historic seaport city of Portsmouth, New Hampshire.

Robert A.. Lenahan is licensed in New Hampshire, Maine and New York and is a member of the the local and national chapters of the AIA and NCARB certified.