121st New York Infantry

The 121st New York Volunteer Infantry Regiment, commonly known as the "Onesers", was a volunteer regiment recruited during the American Civil War from Otsego County and Herkimer County, New York. The Hon. Richard Franchot was appointed colonel of the regiment and authorized to establish his headquarters at Richfield Springs, Otsego County. He proceeded without delay to organize the regiment, and on August 23, 1862 the regiment was mustered into the service of the Union Army. The command at that time consisted of 39 officers and 946 enlisted men. The 121st Regiment proceeded to Washington, arriving there on the morning of September 3, and was assigned provisionally to a brigade under Colonel Gibson with headquarters at Fort Lincoln.

On the march to the South Mountain and Antietam battlefields the regiment was assigned to the Second Brigade, First Division, Sixth Corps and remained with the command during its entire term of service.

Colonel Richard Franchot resigned on September 25, 1862 and selected Colonel Emory Upton, at the time a first lieutenant in the Regular army, under whose command the regiment made a record second to none in the Army of the Potomac.

Organization
The companies were recruited principally from these towns and organized by region:
 * A Company: Manheim, Little Falls, Salisbury, and Danube
 * B Company: Winfield, Plainfield, Litchfield, German Flatts, Columbia, and Stark
 * C Company: Fairfield, Russia, Herkimer, and Newport
 * D Company: Frankfort, Warren, Manheim, Schuyler, Columbia, and Salisbury
 * E Company: Middlefeild, Milford, Cherry Valley, Hartwick, Springfield, Otsego, and Roseboom
 * F Company: Edmeston, Exeter, Unadilla, Otsego, and Maryland
 * G Company: Cherry Valley, Roseboom, Decatur, Middlefield, Westford, Worcester, and Herkimer
 * H Company: Little Falls, Richfield, Salisbury, and Otesego
 * I Company: Milford, Laurens, Morris, Wochester, Pittsfield, Hartwick, and German Flatts
 * K Company: Laurens, New Lisbon, Oneonta, Burlington, Otesgo, Butternuts, Pittsfield, and Plainfield