April 16, 1861
William L. Patterson was mustered into the 1st Ohio Volunteer Infantry, Co. C (Dayton Light Guards) on April 16, 1861 for a 3-month enlistment. He was 22 years old. His rank was 1st Sergeant.
The 1st OVI was organized at Columbus, Ohio, on April 18, 1861, in response to the April 15, 1861, call of the President for volunteers to serve “three months.” The regiment was composed of companies from different parts of the state, most of which were prominent militia organizations of the State. The Regiment was ordered to Washington, D.C. at once and left Columbus on the morning of April 19, 1861. It was mustered into Federal service on April 29, 1861, at Lancaster, PA. On its arrival in Washington, D.C., the 1st OVI was assigned to General Schenck’s Brigade of General Tyler’s Division.