According to the Civil War Book of Lists, the first Union soldier killed was Pvt. Daniel Hough, Co. E, 1st U.S. Artillery, due to the premature discharge of a cannon being used to fire a salute during evacuation ceremonies after the surrender of Fort Sumter.

The same source states that the first Union soldiers killed by hostile action were Pvts. Sumner Needham, Luther C. Ladd, Addison O. Whitney, and Charles A. Taylor, all of the 6th Massachusetts Volunteers, when the regiment was attacked by a secessionist mob as it marched through Baltimore on April 19, 1861.