B & O Railroad Museum

The Baltimore & Ohio Railroad opened its first regular passenger service on May 22 1830, running a horse‑drawn train the 13 miles from Mount Clare to Ellicott Mills, and the brick Mount Clare station was later constructed in 1851. A roundhouse designed by Ephraim Francis Baldwin was added in 1884, forming the core of what would become the museum’s historic complex. The Baltimore & Ohio Transportation Museum opened to the public on July 4 1953 at the former Mount Clare station and roundhouse, and it now holds the largest collection of 19th‑century locomotives in the United States. After the B&O Railroad ceased operations, CSX deeded the property and its collection to an independent, not‑for‑profit organization in 1990, providing a $5 million endowment; the museum affiliated with the Smithsonian Institution in 1999. A roof collapse on February 17 2003 damaged the roundhouse, which was repaired and reopened on November 13 2004, and a new service facility opened in 2005, while the site received a National Historic Landmark designation in 1961 and a National Park Service Underground Railroad Network to Freedom designation in 2021.