was blamed for the high casualties taken on the first day at the Battle of Shiloh. 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 reached 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. Preparing for battle On July 3, acting on his own without orders from his superiors or informing them of his intentions, Wallace dispatched Brig. Gen. Erastus B. Tyler and men from the 1st Maryland Infantry and 3rd Maryland Infantry, Potomac Home Brigade, to Monocacy Junction to establish defensive positions. After Garrett's agents reported the Confederate attack at Harpers Ferry, Wallace relayed the information to Gen. Henry Halleck, then ordered his brigades at Baltimore to be ready to move. Wallace departed for Monocacy Junction on July 4 to assess its defenses. Uncertain whether Baltimore or Washington was the Confederate objective, Wallace knew he had to delay their approach until reinforcements could reach either city. Wallace saw Monocacy Junction, also called Frederick Junction, southeast of Frederick, as the most logical point to defend Baltimore and Washington. A plain extended north and west from the river at Monocacy Junction to the Catoctin Mountains, away. From Monocacy Junction, the B&O Railroad's bridge crossed the river at the foot of a bluff. A wooden bridge provided the Georgetown Pike access to Washington across the Monocacy River, a short distance downriver, while a stone bridge took Baltimore Pike across the Monocacy upriver. Two blockhouses, one near the junction and another on the bluff above the railroad bridge, provided additional protection. A 24-pound howitzer was installed at the blockhouse on the bluff. If Wallace could stretch his force across of the stream to protect both turnpike bridges, the railroad bridge, and several river fords, he could force Early to disclose the strength and objective of the Confederate force and delay him as long as possible. Initially, Wallace's forces along the river at Monocacy Junction consisted of Tyler's brigades and a cavalry force of 230 troopers from the 8th Illinois