In the meantime, agents of the Baltimore and Ohio Railroad at Cumberland, Maryland, and Harpers Ferry reported signs of Early's advance on June 29. John W. Garrett, the president of the railroad and a Union supporter, passed this intelligence and subsequent reports were passed to Wallace on July 3. Garrett was concerned about protecting a railroad bridge at Monocacy Junction, Maryland, where it crossed the Monocacy River. The bridge was important to rail connections at Harpers Ferry and points farther west, so Wallace agreed to bring a force to the Monocacy to protect it.