William H. Offen was born on October 3, 1837 in Danbury, Connecticut. As per the 1860 census, he lived in New Canaan, Connecticut, was a shoemaker and was married. He enlisted on October 20, 1863 in Stamford, Connecticut, in Company G of the 10th Connecticut Infantry Regiment, for a two-year period. He was mustered out on September 10, 1865. In 1870, he lived in Stamford, CT.
He supposedly participated in the Siege of Petersburg, Virginia. He died on August 20, 1910.
WPA locations 8556 on West Drive (now Lander Dr). He is on Richard Lander's list and on Ancestry.com: 1861-65 NARA M535/roll 12. The Connecticut Data Base states that he enlisted on October 16, 1863 and reenlisted on January 11, 1864 in a Veterans Detachment. Catalogue of the 6-11th Regiments of Infantry, First Light Battery and First Battalian of Cavalry of Connecticut Volunteers, page #102.