Background
O'Reilly was born in Columkille, County Longford, and embarked for the United States in January 1825 with the intention of studying for the priesthood.
O'Reilly was born in Columkille, County Longford, and embarked for the United States in January 1825 with the intention of studying for the priesthood.
He attended the Seminary of Montreal in Quebec, Canada, before completing his theological studies at St. Mary's Seminary in Baltimore, Maryland.
He served as Bishop of Hartford from 1850 until his death in 1856. He was ordained a priest by Bishop Francis Kenrick on October 13, 1831. He then served in New York City and Brooklyn, where he distinguished himself for his heroism during the cholera outbreak in 1832 and twice fell victim to the disease himself.
He was transferred to Rochester in December 1832, and remained there until he became vicar general of the Diocese of Buffalo in 1847. On August 9, 1850, O'Reilly was appointed the second Bishop of Hartford, Connecticut, by Pope Pius IX. He received his episcopal consecration on the following November 10 from Bishop John Timon, C.M., with Bishops John McCloskey and John Bernard Fitzpatrick serving as co-consecrators, at Rochester. O'Reilly visited Europe in 1855 and embarked, on his return voyage, in January 1856 on the SS Pacific, which sailed from Liverpool for New York.
The ship, however, was not heard of for over 130 years, when in 1991 her wreckage was identified in the Irish Sea off the coast of Wales.
He worked to secure priests for the diocese, and defended Catholics from the anti-Catholic movements of the era, such as Know-Nothingism.