The Costen House is a historic U.S. home located at 206 Market Street, Pocomoke City, Maryland, United States. Dr. Isaac Thomas Costen built the house c. 1870s and members of his family lived there for over a century. Dr. Costen became the first Mayor of Pocomoke City. The house currently serves as The Isaac Costen House Museum. The Costen House was listed on the National Register of Historic Places in 1975.