The oldest section of the house was built around 1835 for George Allen, who lived next door. Listed as a “gentleman” in the 1850 census, Allen held several public offices, and he is said to have brought old New York cart horses to Roslyn to end their lives in comfort. The original house was one-and-a-half story, 3 bay wide, having a pitched roof, the ridge of which extended from north to south. The original chimney was rectangular in cross-section and was included inside the north wall of the principal block of the house. The home was renovated in four stages starting Circa 1835 with the final stage Circa 1974.

During December of 1974 there was a fire and the house was badly burned. The original doorways and the Queen Anne Revival principal staircase was scorched. Mr. Robert Augenstein, who owned the building from circa 1950-1974 cleared away the interior debris and provided some protection from the elements by covering the surviving roof framing. In the fall of 1976 almost 2 years later, the building was bought by Dr. and Mrs. Roger Gerry who were concerned about the possible demolition of the George Allen Tenant House on the Main Street Historic District. With help from John Stevens, the architectural historian for the Bethpage Village Restoration, it was decided that restoration was necessary and the Gerry’s bought the home. It had been decided that the home would be restored to its Stage II appearance (circa 1845) and to retain the Stage III (circa 1895-1905) south entrance hallway and stairway because of their fine provincial quality. It was impossible to determine how this area looked during Stage I (circa 1835). By the end of 1977 the exterior restoration was virtually complete; the interior restoration continued in 1979, 1980 and 1981. The George Allen Tenant House is now the headquarters for the Roslyn Landmark Society.

The Roslyn Landmark Society headquarters currently has paintings and photographs on display by local artists as well as pictures from the 18th & 19th century Roslyn.