The 12th New York Infantry Regiment was an infantry regiment in the Union Army during the American Civil War. Service 3 Month Service of the 12th New York State Militia The 12th New York Volunteer Infantry is sometimes confused with the 12th New York State Militia, a distinguished regiment formed in 1847 and which left New York City on April 21, 1861, for three months' service under the command of Colonel Daniel Butterfield. The 12th New York State Militia was not the same regiment as the 12th New York volunteers, though in February 1862 it did furnish a five-company battalion for the 12th Volunteers, and Henry A. Weeks of the militia regiment took command of the 12th Volunteers as a result. Remaining 12th New York militiamen stayed in New York City with their regiment, which was activated for federal service twice more during the war. Compounding the 12th Volunteers/12th Militia confusion is the fact that Butterfield at one point commanded the brigade in which the 12th New York Volunteers served. Also, as indicated by inscriptions on the 12th New York's monument at Gettysburg, at least some of its veterans considered the two 12th New York regiments to be one and the same. 2 Year The 12th New York Volunteer Infantry was organized at Elmira, New York and mustered in May 8, 1861 for two years' state service under the command of Colonel Ezra L. Walrath. On May 13, 1861 the regiment was re-mustered for three months' federal service and again re-mustered on August 2, 1861 for two years' state service. The regiment was attached to Richardson's Brigade, Tyler's Division, McDowell's Army of Northeast Virginia, June to August 1861. Richardson's Brigade, Division of the Potomac, to October 1861. Wadsworth's Brigade, McDowell's Division, Army of the Potomac, to March 1862. Butterfield's 3rd Brigade, Porter's 1st Division, III Corps, Army of the Potomac, to May 1862. 3rd Brigade, 1st Division, V Corps, to May 1863. Headquarters, V Corps, to June 1864. The 12th New York Infantry mustered out of the service on May 17, 1863. Men who had enlisted for three years' service were consolidated into two companies and served duty as Provost Guard for Headquarters of V Corps under the command of Captain Henry W. Ryder. These two companies ceased to exist on June 2, 1864 when their members were transferred to the 5th New York Infantry as Companies E and F.