12th New Hampshire Volunteer Infantry The 12th New Hampshire Volunteer Infantry was an infantry regiment that served in the Union Army during the American Civil War . Service . The 12th New Hampshire Infantry was organized in Concord , New Hampshire and mustered in for a three - year enlistment on September 10 , 1862 under the command of Colonel Joseph Haydn Potter . The regiment was attached to Casey ' s Division , Military District of Washington , to December 1862 . 2nd Brigade , 3rd Division , III Corps , Army of the Potomac , to June 1863 . 1st Brigade , 2nd Division , III Corps , Army of the Potomac , to July 1863 . Marston ' s Command , Point Lookout , Maryland , District of St . Mary ' s , to April 1864 . 2nd Brigade , 2nd Division , XVIII Corps , Department of Virginia and North Carolina , to December 1864 . 2nd Brigade , 3rd Division , XXIV Corps , Department of Virginia , to June 1865 . The 12th New Hampshire Infantry mustered out of service June 21 , 1865 . Detailed service . Left New Hampshire for Washington , D . C . , September 27 , 1862 . Duty in the defenses of Washington until October 1862 . Moved to Point of Rocks , Md . , October 18 ; then to Pleasant Valley October 19 . Moved to Warrenton , Va . , October 24 - November 16 , and to Falmouth November 18 – 24 . Battle of Fredericksburg December 12 – 15 . Burnside ' s 2nd Campaign ( " Mud March " ) January 20 – 24 , 1863 . Duty at Falmouth until April . Chancellorsville Campaign April 27 - May 6 . Battle of Chancellorsville May 1 – 5 . Gettysburg Campaign June 11 - July 24 . Battle of Gettysburg July 1 – 3 . Ordered to Point Lookout , Md . , July 26 , and duty there guarding prisoners until April 7 , 1864 . Moved to Yorktown April 7 , then to Williamsburg . Butler ' s operations on south side of the James River and against Petersburg and Richmond May 4 – 28 . Swift Creek ( or Arrowfield Church ) May 9 – 10 . Operations against Fort Darling May 12 – 16 . Battle of Drewry ' s Bluff May 14 – 16 . Bermuda Hundred May 16 – 27 . Moved to White House , then to Cold Harbor , May 27 – 31 . Battles about Cold Harbor June 1 – 12 . Before Petersburg June 15 – 19 . Siege of Petersburg and Richmond June 16 , 1864 to April 2 , 1865 . Mine Explosion , Petersburg , July 30 , 1864 ( reserve ) . Duty on the Bermuda Front August 26 to December , and in trenches before Richmond until April 1865 . Occupation of Richmond April 3 . Guard and provost duty at Manchester until June . Service at Gettysburg . On July 2 , 1863 , the 12th New Hampshire was heavily engaged north of the Klingel Farm , facing attack by Wilcox ' s Alabama brigade . The regiment had 224 men on the field that day , of whom 26 were killed and 73 were wounded ( an additional six men would die of their wounds ) . Captain John F . Langley ( Company F ) was in command , and was wounded when the regiment was ordered to withdraw . Lieutenant William H . H . Fernel ( Company I ) took command and was able to rescue some 50 Union soldiers who were captured during the withdrawal . The following day , only 50 men were fit for duty under the command of Captain Thomas E . Barker ( Company B ) . Placed near the center of the Union line , they helped repulse Pickett ' s charge . Casualties . The regiment lost a total of 320 men during service ; 11 officers and 170 enlisted men killed or mortally wounded , 1 officer and 138 enlisted men died of disease .