Harvard Regiment leaves Boston.

Officially the Twentieth Massachusetts Volunteer Infantry, it leaves from Camp Meigs and subsequently arrives in Maryland. Officers include Oliver Caspar Crowninshield, Wendell Holmes Jr., James and William Lowell, Francis Palfrey, and Paul Revere. The unit subsequently sees action in almost every major battle waged against Confederate forces under the command of Gen. Robert E. Lee, including Ball’s Bluff and Gettysburg. It also suffers the highest number of casualties of any New England regiment. Initially made up of 800 soldiers, it has fewer than 400 members, and only 44 original members in the regiment, when the war ends.