James O'Reilly (October 10, 1855—December 19, 1934) was an Irish Roman Catholic clergyman who, after arriving in the United States and serving as a priest, became the second Bishop of Fargo (1910–1934). On December 18, 1909, O'Reilly was appointed the second Bishop of Fargo, North Dakota, by Pope Pius X. He received his episcopal consecration on May 19, 1910 from Archbishop John Ireland, with Bishops James McGolrick and James Trobec serving as co-consecrators. He served as bishop for the next twenty-four years, until his death just over two months past his 79th birthday.