Seventh Ohio Volunteer Infantry, Company E. He was promoted to Captain for brave and meritorious service. Captain Wilcox participated in these battles: Cross Lanes, Virginia, where he was captured by the enemy and confined to various prisons; Dumfries, Virginia; Chancellorsville, Virginia; Gettysburg, Pennsylvania; Lookout Mountain and Missionary Ridge, Tennessee; and several battles in the state of Georgia. Wilcox mustered out of the 7th Infantry on July 6, 1864. Soon, he reenlisted and became Colonel of the 177th Ohio Volunteer Infantry. On June 24, 1865, Colonel Wilcox was mustered out with regiment at Greensboro, North Carolina.
After the war was over, Wilcox resumed his work as a civil engineer. He worked on the construction of railroads, including the Union Pacific and the Canada Southern. A publication of the University of Michigan Alumni Association reports that Arthur Tappan Wilcox contracted yellow fever while working on bridges in Central America. He died of the disease at Port Limon, Costa Rica, on October 24, 1902. A biographical sketch of Arthur T. Wilcox which appeared in the book Itinerary of the Seventh Ohio Volunteer Infantry, 1861-1864 closed with this statement about Colonel Wilcox: “He was a zealous officer and a brave man.”