They also aided in the hunt for John Wilkes Booth and served as President Lincoln's honor guard while he lay in state under the rotunda.

Lincoln gave them the nickname of "Farnsworth's Abolitionist Regiment" when he watched them march past the White House.

The regiment was commissioned on August 11, 1861, and was assembled for service in St. Charles, Illinois, on September 18, 1861, at the site donated by Colonel Farnsworth called Camp Kane.

They deployed west of Gettysburg on June 30, 1863, under the command of Colonel William Gamble, and waited for oncoming Confederates that arrived early the following morning.

The 8th, along with the rest of the brigade, performed a fighting withdrawal toward McPherson's Ridge, delaying the Confederate division of Henry Heth for several hours and allowing the Union I Corps to arrive.