Raised in Philadelphia in mid-1864, the regiment was made up of Hundred Days Men in an effort to augment existing manpower for an all-out push to end the war within 100 days, and spent most of its service guarding Confederate prisoners of war at Rock Island.

The regiment was organized at Camp Cadwalader near Philadelphia on 22 July 1864, under the command of volunteer officer Colonel John R. Haslett, who had worked as a house painter before the war.

[2] According to Samuel Penniman Bates' official history, "a large proportion" of the regiment were "well schooled soldiers."

Shortly after its organization, the regiment was sent to Camp Bradford at Mankin's Woods near Baltimore on 29 July,[3] where it trained for two weeks.

The number of guards was insufficient for the task, and this placed pressure on the 197th, which repeated the 133rd Illinois Infantry's practice of firing upon prisoners, but was otherwise undistinguished.