The 15th New Hampshire was organized between October 6th and 16th 1862 in Concord, New Hampshire as a nine month regiment. The men of the regiment came mostly from the counties of Belknap, Cheshire, Grafton, Hillsborough, Merrimack, Rockingham, Strafford, and Sullivan, New Hampshire. They formed under the command of Colonel John W Kingman.
The 15th left New Hampshire November 13th 1862 for New York, where they would sail for New Orleans, Louisiana. The regiment arrived in Louisiana December 26th 1862. They were placed in the Union Department of the Gulf a part of William T Sherman’s Division. The men of the 15th settled in at Camp Parapet, Louisiana serving there on duty until May 1863. When the 1863 campaign season got going they were moved to Springfield Landing, Louisiana, and then onto service in the Siege of Port Hudson, Louisiana from May 27th through July 9th 1863.
The men of the 15th were mustered out of Union service August 13th 1863 at Concord, New Hampshire. During their time in the army the 15th had 27 men who killed in action or died from their wounds, and another 134 who died from disease.