Citation

On board the U.S.S. Brooklyn during action against rebel forts and gunboats and with the ram Tennessee, in Mobile Bay, 5 August 1864. Despite severe damage to his ship and the loss of several men on board as enemy fire raked her decks, Sgt. Denig fought his gun with skill and courage throughout the furious 2-hour battle which resulted in the surrender of the rebel ram Tennessee and in the damaging and destruction of batteries at Fort Morgan.

http://www.cmohs.org/recipient-detail/351/denig-john-henry.php

http://en.wikipedia.org/wiki/J._Henry_Denig

John Henry Denig (September 8, 1838 – December 10, 1876) was a United States Marine Corps sergeant serving aboard the USS Brooklyn during the American Civil War. He received the Medal of Honor for his actions in 1864 during the Battle of Mobile Bay.

http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=7441995