LEONARDTOWN, MD – St. Mary’s County Government’s Museum Division invites the community to attend a special remembrance ceremony on Sunday, April 26, 2026, at 2 p.m. honoring the 87 lives lost in the Black Diamond Disaster, a tragic and often-forgotten Civil War-era maritime accident that occurred near St. Clement’s Island during the hunt for presidential assassin John Wilkes Booth.
Community members are encouraged to gather at the St. Clement’s Island Museum site for a wreath-laying ceremony commemorating the disaster, which occurred on April 23, 1865, when the barge Black Diamond and the steamer Massachusetts collided in the Potomac River.
Following the assassination of President Abraham Lincoln, the Quartermaster Corps stationed the Black Diamond off St. Clement’s Island on picket duty to help prevent John Wilkes Booth from crossing the Potomac River during his attempted escape. Meanwhile, the steamer Massachusetts was traveling from Alexandria, Virginia, to Fortress Monroe when it struck the Black Diamond in the darkness. The collision sank the vessel in under three minutes, tragically claiming 87 lives.
Following the ceremony, a concert and reception will take place at 2:30 p.m. at nearby Potomac Gardens featuring a performance by the 8th Green Machine Regiment Band, an early American brass band known for performing 19th-century music on authentic period instruments and mouthpieces.
Guests will also have the opportunity to meet Karen Stone, author of Shipwreck on the Potomac: Disaster in Pursuit of Lincoln’s Killer, during a book signing reception.
Later that evening, the 2026 Dinner and a Cruise Series (ticketed event) will kick off with the program “The Potomac River and John Wilkes Booth,” presented by local author and Booth historian Michael Kauffman. During the cruise, Kauffman will explore the strategic significance of the Potomac River during the Civil War and its central role in Booth’s escape following Lincoln’s assassination.
For more information about the event, or to reserve tickets for the cruise, please call St. Clement’s Island Museum at (301) 769-2222 or visit Facebook.com/SCIMuseum.
About the St. Mary’s County Museum Division
The St. Mary’s County Museum Division was established by the Commissioners of St. Mary’s County to collect, preserve, research, and interpret the historic sites and artifacts which illustrate the natural and cultural histories of St. Mary’s County and the Potomac River.
These sites include St. Clement’s Island Museum, Piney Point Lighthouse Museum, the Old Jail Museum, and the Drayden African American Schoolhouse.
With this as its charter, the Museum Division serves as a resource, liaison, and community advocate for all St. Mary’s County public and private cultural assets. For more information, please visit: museums.stmarysmd.com.