40th New York Infantry in the American Civil War

Overview

The 40th New York Infantry (Three Years’ Service), also known as the “Mozart Regiment,” was an infantry regiment that served in the Union Army during the American Civil War. Organized primarily in New York City, the regiment also included four companies from Massachusetts. It was mustered into United States service at Yonkers, New York, between June 14 and June 27, 1861, for a three-year term. The 40th New York served in the Eastern Theater and was attached to various brigades and divisions within the Army of the Potomac. The regiment became notable for its high casualty rate and its reputation as one of the hardest-fighting New York regiments.

Organization & Service

The 40th New York Infantry was organized at Yonkers, New York, and mustered into service from June 14 to June 27, 1861. The regiment left New York for Washington, D.C., on July 4, 1861, with approximately 1,000 men. After a brief encampment in Washington, the regiment moved to Alexandria, Virginia, where it participated in the construction of Fort Ward and performed guard duty along the Orange & Alexandria Railroad during the summer of 1861.

Initially assigned to Howard’s Brigade, Potomac Division, on August 4, 1861, the regiment was later attached to Sedgwick’s Brigade, Heintzelman’s Division, and spent the winter near Alexandria. In March 1862, as part of the 2nd Brigade, 3rd Division, 3rd Corps, Army of the Potomac, the regiment moved to the Peninsula, participating in the Siege of Yorktown and the Battle of Williamsburg. The 40th New York fought at Fair Oaks, suffering significant losses, and was engaged throughout the Seven Days’ Battles. After a period at Harrison’s Landing, the regiment joined General Pope’s campaign in Virginia, fighting at Second Bull Run, Chantilly, and Fredericksburg, each time incurring heavy casualties.

In September 1862, recruits from the 87th New York were consolidated into the regiment. After Chancellorsville in May 1863, the 40th was reduced to a battalion of five companies. On May 30, 1863, three-year men from the 37th, 38th, 55th, and 101st New York were assigned to the regiment. As part of the 3rd Brigade, 1st Division, 3rd Corps, the regiment fought at Gettysburg, Kelly’s Ford, and in the Mine Run Campaign. The winter of 1863-64 was spent near Brandy Station, where many members reenlisted and new recruits joined.

In March 1864, the regiment was assigned to the 1st Brigade, 3rd Division, 2nd Corps, and participated in the Overland Campaign, including the Wilderness, Spotsylvania, the Po River, North Anna, Totopotomoy, and Cold Harbor. In July 1864, original members not reenlisted were mustered out in New York City, and the regiment was consolidated into six companies, later reinforced by veterans from the 74th New York. The 40th New York continued to serve before Petersburg, engaging in actions at the Weldon Railroad, Deep Bottom, Strawberry Plains, Poplar Spring Church, Boydton Road, Hicksford Raid, Hatcher’s Run, Fort Stedman, White Oak Ridge, the final assault on Petersburg, and the pursuit to Appomattox. The regiment was mustered out at Washington, D.C., on June 27, 1865.

Engagements & Campaigns

• Siege of Yorktown (April–May 1862)
• Battle of Williamsburg (May 1862)
• Battle of Fair Oaks (May–June 1862)
• Seven Days’ Battles (June–July 1862)
• Second Battle of Bull Run (August 1862)
• Battle of Chantilly (September 1862)
• Battle of Fredericksburg (December 1862)
• Chancellorsville Campaign (April–May 1863)
• Battle of Gettysburg (July 1863)
• Kelly’s Ford (November 1863)
• Mine Run Campaign (November–December 1863)
• Wilderness Campaign (May 1864)
• Battle of Spotsylvania Court House (May 1864)
• Battle of the Po River (May 1864)
• North Anna (May 1864)
• Totopotomoy (May 1864)
• Cold Harbor (June 1864)
• Siege of Petersburg (June 1864–April 1865)
• Weldon Railroad (August 1864)
• Deep Bottom (August 1864)
• Strawberry Plains (August 1864)
• Poplar Spring Church (September 1864)
• Boydton Road (October 1864)
• Hicksford Raid (December 1864)
• Hatcher’s Run (February 1865)
• Fort Stedman (March 1865)
• White Oak Ridge (March–April 1865)
• Final Assault on Petersburg (April 2, 1865)
• Pursuit to Appomattox (April 1865)

Casualties

• Killed or died of wounds: 238
• Died from accident, imprisonment, or disease: 172
• Total deaths: 410

According to Fox, the 40th New York Infantry lost more men killed and wounded than any other New York regiment except the 69th. If casualty figures vary in other sources, these numbers are based on regimental and state reports.

Field Officers & Commanders

• Colonel Edward J. Riley
• Colonel Thomas W. Eagan
• Colonel Madison M. Cannon
• Lieutenant Colonel Thomas W. Eagan
• Lieutenant Colonel Nelson A. Gesner
• Lieutenant Colonel P. Allen Lindsay
• Lieutenant Colonel Augustus J. Warner
• Lieutenant Colonel Madison M. Cannon
• Lieutenant Colonel Thomas Crawford
• Major Richard T. Halstead
• Major Albert S. Ingalls
• Major P. Allen Lindsay
• Major Augustus J. Warner
• Major Emmons F. Fletcher
• Major Madison M. Cannon
• Major Thomas Crawford
• Major Augustus W. Keene

Regimental Roster

The complete roster of officers and enlisted men who served in the 40th New York Infantry (Three Years’ Service) is available for genealogical and historical research. This roster includes names, ranks, and service details as recorded in official state and regimental records.

To view the full roster, visit the 40th New York Infantry (Three Years’ Service) Roster page.

Sources & References

• Official Records of the Union and Confederate Armies, Series I, Volumes 5, 9, 11, 12, 19, 21, 25, 27, 29, 36, 40, 46
• 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, Volume 2