12th New York Infantry in the American Civil War

Overview

The 12th New York Infantry (also known as the “Onondaga Regiment”) was an infantry regiment organized in New York State for Union service during the American Civil War. The regiment was initially mustered into United States service for a three months’ term at Elmira on May 13, 1861, and subsequently reorganized for a two years’ term. The unit drew six companies from Syracuse, with the remaining companies recruited from Liverpool, Homer, Batavia, and Canastota. The 12th New York served primarily in the Eastern Theater and participated in several major campaigns and battles.

This regiment is distinct from the 12th New York Infantry (Three Months’ Service).

Organization & Service

The 12th New York Infantry was mustered into federal service for a two years’ term on August 13, 1861, following its initial three months’ service. After its reorganization in January 1862, the regiment was consolidated into a battalion of five companies, stationed near Washington, D.C., at Forts Ramsay, Tillinghast, Craig, and Buffalo. In February 1862, five companies from the reorganized 12th New York State Militia joined the regiment, bringing it to full strength.

The regiment was attached to Butterfield’s Brigade, Porter’s Division, 3rd Corps, and moved via Fortress Monroe to Hampton and Yorktown, taking part in the siege of Yorktown. In May 1862, it was assigned to the 3rd Brigade, 1st Division, 5th Corps, and participated in the Seven Days’ Battles. The 12th New York was engaged in General Pope’s campaign in Virginia, suffering significant losses at the Second Battle of Bull Run. The regiment was in reserve at South Mountain and Antietam, and later fought at Fredericksburg in December 1862 before wintering at Falmouth, Virginia.

Original members who did not reenlist were mustered out at Elmira on May 17, 1863. The remaining three years’ men were consolidated into two companies and transferred to the 5th New York Veteran Infantry on June 2, 1864. From May 1864, these companies served as provost guard with the 5th Corps and were present during the Wilderness Campaign.

Engagements & Campaigns

• Blackburn’s Ford
• First Battle of Bull Run (in reserve)
• Siege of Yorktown
• Seven Days’ Battles
• Second Battle of Bull Run
• South Mountain (in reserve)
• Antietam (in reserve)
• Fredericksburg
• Wilderness Campaign (as provost guard, two companies)

Casualties

The 12th New York Infantry lost a total of 69 men killed or mortally wounded in action, and 68 died from disease or other causes. Total losses, as reported, were 137 men. If figures vary in different sources, these are the most commonly cited numbers in official reports.

Field Officers & Commanders

• Colonel Ezra L. Walrath
• Colonel George W. Snyder
• Colonel Henry A. Weeks
• Colonel Benjamin A. Willis
• Lieutenant Colonel James L. Graham
• Lieutenant Colonel Robert M. Richardson
• Lieutenant Colonel Augustus J. Root
• Lieutenant Colonel William A. Olmstead
• Major John Lewis
• Major Henry A. Barnum
• Major Augustus J. Root
• Major Henry W. Ryder

Regimental Roster

The full roster of the 12th New York Infantry (Two Years’ Service), including officers and enlisted men, is available for genealogical and historical research. This roster provides names, ranks, and other service details as recorded in official state and federal records.

To view the complete roster, visit the 12th New York Infantry (Two Years’ Service) Roster page.

Sources & References

• Official Records of the Union and Confederate Armies, Series I, Vol. 2, 5, 9, 11, 12, 19, 21, 25
• New York State Adjutant General’s Reports
• Dyer, Frederick H. “A Compendium of the War of the Rebellion”
• Fox, William F. “Regimental Losses in the American Civil War”
• “The Union Army,” Federal Publishing Company, 1908, Vol. 2