James Gwyn (November 24, 1828 - July 17, 1906) was an officer in the Union Army during the American Civil War. He immigrated at a young age from Ireland in 1846. At the onset of the war, in 1861, he enlisted & was commissioned as a captain with the 23rd Pennsylvania Volunteer Infantry. He assumed command of the 118th Pennsylvania Regiment in the course of the war. Gwyn led that regiment through many of its 39 recorded battles, including engagements at, Fredericksburg & Gettysburg.