St. Catharine, also known as Dr. Samuel A. Mudd House, is a historic house near Waldorf, Maryland. It is a two-part frame farmhouse with a two-story, three-bay side-passage main house with a smaller two-story, two-bay wing. It features a one-story hip-roofed porch across the facade added in 1928. It was at this house where Dr. Samuel A. Mudd treated the injured John Wilkes Booth. "St. Catharine" has been in the Mudd family since the 1690s. It is operated as a historic house museum.