He was born in 1839/41 (6 (26 probably in 1863/64)). He was born in Ireland (6).
When he enlisted, he was 5 feet 10-1/2 inches tall, and had a fair complexion, blue eyes, and brown hair (6). He had an 'O' in blue on his left hand (6).
He enlisted and was mustered into service on 18 September 1861 (1, 6, 9). He was enlisted for three years, at Philadelphia, Pennsylvania, by Captain Smith (6). He was a private in company C (1, 12-13).
He reenlisted as a veteran volunteer (1).
He was reduced to the ranks (5).
He mustered out on 10 July 1865 with his company (1, 9). He was a private, in company C (12-13).
On 5 August 1871, he successfully applied for a pension (9).
1 Bates, Samuel Penniman. History of Pennsylvania volunteers, 1861-5. Harrisburg: B. Singerly, state printer, 1869-71. 5 volumes. 'Ninety-first regiment', volume 3, pages 186-233. (In the roster)
2 special order 82, HQ 91st PA, 23 September 1864
4 enlisted men's furloughs (John ONeil)
5 company C, List of non-commissioned officers, page 2, corporals (John O'Neill)
6 company C, descriptive roll, entry 55 (John ONiel)
7 consolidated morning report, 91st Pennsylvania, 10 March 1865 (not named)
8 consolidated morning report, 91st Pennsylvania, 12 March 1865 (Corp Oneill)
9 pension index, by regiment, 91st PA Infantry, company C (John O'Neill)
10 'The ninety-first Pennsylvania volunteers', Philadelphia Press, Wednesday 13 May 1863, page 2 (John O'Neille)
11 'The Ninety-first Pennsylvania at Chancellorville', Philadelphia Inquirer 13 May 1863, page 8 (John O'Neille)
12 index to compiled service records of volunteer Union soldiers who served in organizations from the state of Pennsylvania (John O'Niel)
13 index to compiled service records of volunteer Union soldiers who served in organizations from the state of Pennsylvania (John O'Neil)