The attack began at 4:44 am, when the mine exploded, leaving a 200 foot long, 50-60 foot wide crater in the line, some 25 to 30 feet deep in places. A division under General Ledlie led the attack, and marched straight into the hole in the line. They were to continue on towards Cemetery Hill, but were bogged down within the crater. Two other divisions followed them in, to occupy the grounds on both flanks of Ledlie, while he continued forward.
6th NH Infantry: 1 officer and 8 enlisted men
9th NH Infantry: 1 officer and 22 enlisted men
11th NH Infantry: 22 enlisted men
The 4th NH Infantry, which was part of the X Corps (attached to the XVIII), suffered 13 dead in the battle.
Jackman, Lyman and Hadley, Amos. History of the Sixth New Hampshire Regiment in the War for the Union. Concord, NH: Republican Press Association, 1891.
Lord, Edward Oliver. History of the Ninth Regiment, New Hampshire Volunteers in the War of the Rebellion. Concord, NH: Republican Press Association, 1895.
Cogswell, Leander W. A History of the Eleventh New Hampshire Regiment, Volunteer Infantry in the Rebellion War, 1861-1865. Concord, NH: Republican Press Association, 1891.
Websites:
https://en.wikipedia.org/wiki/Battle_of_the_Crater
http://www.civilwar.org/battlefields/the-crater.html?tab=facts