On April 17, the Sixth Massachusetts Militia departed from Boston, Massachusetts, arriving in New York the following morning and Philadelphia by nightfall. On April 19, the unit headed on to Baltimore, where they anticipated a slow transit through the city. Because of an ordinance preventing the construction of steam rail lines through the city, there was no direct rail connection between the Philadelphia, Wilmington and Baltimore Railroad's President Street Station and the Baltimore and Ohio Railroad's Camden Station (ten blocks to the west).Rail cars that transferred between the two stations had to be pulled by horses along Pratt Street....

...Sometime after leaving Philadelphia, the unit's colonel, Edward F. Jones, received information that passage through Baltimore "would be resisted". According to his later report, Jones went through the railroad cars and gave this order:

"The regiment will march through Baltimore in column of sections, arms at will. You will undoubtedly be insulted, abused, and, perhaps, assaulted, to which you must pay no attention whatever, but march with your faces to the front, and pay no attention to the mob, even if they throw stones, bricks, or other missiles; but if you are fired upon and any one of you is hit, your officers will order you to fire. Do not fire into any promiscuous crowds, but select, any man whom you may see aiming at you, and be sure you drop him."

Indeed, as the militia regiment transferred between stations, a mob of anti-war supporters and Southern sympathizers attacked the train cars and blocked the route. When it became apparent that they could travel by horse no further, the troops got out of the cars and marched in formation through the city. However, the mob followed the soldiers, breaking store windows[citation needed] and causing damage until they finally blocked the soldiers. The mob attacked the rear companies of the regiment with "bricks, paving stones, and pistols." In response, several soldiers fired into the mob, beginning a giant brawl between the soldiers, the mob, and the Baltimore police. In the end, the soldiers got to the Camden Station, and the police were able to block the crowd from them. The regiment had left behind much of their equipment, including their marching band's instruments.