Some time later, George Hadlock, Edwin's son, sold the building to William Otis Sawtelle, a physics professor at Haverford College who spent his summers on the island.

The plain weatherboarded structure sits at the water's edge, with an irregular pattern of windows, most of which were replaced in the early 20th century.

The Islesford Historical Museum is a 1½ story fireproof brick structure built in 1927 in the Georgian Colonial Revival style.

The main block has two prominent interior chimneys and a formal entrance with a semicircular dormer-fanlight.

[2] The buildings, the Sawtelle gravesite and 1.3 acres (0.53 ha) were acquired by the National Park Service in 1948.