The Civil War’s first casualties from hostile fire came not on soil in a Confederate State, but in Baltimore, Md., on April 19, 1861. (A gun explosion during Ft. Sumter surrender ceremonies had killed two Union soldiers.)
Maryland was a border State that was divided over its loyalty to the Union or the Southern cause. President Abraham Lincoln had received just 2 percent of Baltimore’s vote for President, with most of the votes going to Southern Democratic candidate John Breckinridge. Most of the State’s western counties also went for Breckinridge.
On Feb. 18, 1861, the Maryland legislature called a secession convention. The session ended — but did not adjourn — the next day without a decision.
On April 19, Union troops making up the 6th Massachusetts Regiment marched through Baltimore en route to Washington. They were surrounded by local citizens who began jeering them. Events escalated until finally the troops opened fire and fighting began in the streets. When the dust cleared, four soldiers from 6th Massachusetts were dead and 36 were wounded. Twelve citizens were dead and an unknown number were injured.
Lincoln quickly sent troops to occupy Baltimore. He suspended habeas corpus, and Secretary of War Simon Cameron ordered Maj. George McClellan to arrest all pro-Southern members of the Legislature prior to Sept. 17, the day the Legislature had scheduled to reconvene its secession convention. Pro-secession city officials were also arrested, including Baltimore Mayor George Brown.
Bruce Catton writes in The Civil War: “All of this, of course, was plainly illegal, the Federal government was not going to let the secessionists cut Washington off from the rest of the North, no matter what it had to do to prevent it; with dissident legislators in jail, the Unionist governor of Maryland had little trouble holding the state in the Union.”
After pro-secessionist legislators were removed from the equation, the Maryland Legislature was unable to establish a quorum to consider secession; and Maryland, at the point of the gun, was kept in the Union.