Illinois Civil War Soldier.
Theodore Watson, a young man from Hillsboro, Montgomery County, Illinois, was mustered into H Company, 3rd Illinois Volunteers in Springfield, Illinois, on April 26, 1861. The 3rd was moved to Cairo, Illinois, for garrison duty at Camp Defiance, attached to Captain Prentiss's Brigade. Originally a ninety-day unit, the 3rd became the 9th Illinois Regiment under Prentiss, with a three-year enlistment period. Watson chose not to re-enlist and was mustered out July 26, 1861.
From the description of Theodore Watson letters, 1861, Apr. 27-July 7. (Newberry Library). WorldCat record id: 54999683