St. Mary's Catholic Church is a parish of the Roman Catholic Church located near Bryantown, Maryland, in the Roman Catholic Archdiocese of Washington. Established in 1793, it operates a parochial school and houses a large cemetery. St. Mary's Cemetery is most notably the final resting spot of Dr. Samuel Mudd, a physician who set the leg of John Wilkes Booth the day after U.S. President Lincoln's assassination on April 14, 1865. As such, it is a stop on the Booth's Escape Scenic Byway.
Although Catholic worship in Bryantown was recorded as early as 1654, land for a log cabin church was not set aside until 1743. Construction on the current church began in 1846. It was damaged by fire in 1963, rebuilt, and rededicated in 1966.