The old St. Mary's Rectory is a gable-front 21⁄2-story frame dwelling of three by three bays, built in 1849 and enlarged to twice its size in 1856, and located in Aquasco, Prince George's County, Maryland.

The floor plan exemplifies a style typical of the dwellings of successful landowners and merchants of the mid-19th century in Prince George's County.

Italianate elements include the heavy bracketing of the exterior cornice and the tripartite window in the north gable end.

Rehabilitated by its present owners, the rectory contains a significant amount of original fabric and is little changed from its mid-19th-century appearance.

It is located in Aquasco, one of three remaining examples of a well-preserved agricultural community in Prince George's County.