(c. 1833 - 1873)
Home State: New York
Command Billet: Commanding Regiment
Branch of Service: Infantry
Unit: 24th New York Infantry
At age 28 he raised a Company of troops and enrolled on 24 April 1861 at Oswego and mustered as Captain, Company A, 24th New York Infantry on 17 May.
On the Campaign
In command of the 24th New York Infantry as senior officer present after 30 August, he led the regiment in Maryland. They were at the front of the Division during the assault on Frostown and Turner's Gaps on South Mountain on 14 September 1862. General Hatch later reported:
Captain John D. O'Brian, commanding the brave Twenty-fourth New York, attracted the attention of all by his energy and activity.
He was severely wounded in the right leg in action in Miller's Cornfield at Antietam on the morning of 17 September 1862.
The rest of the War
His leg was amputated at a field hospital on the battlefield and he was discharged for disability on Christmas Eve 1862. He began receiving a Federal invalid pension about February 1863.
References & notes
His service from the Adjutant General.1 Wound and surgical details from the MSHWR;2 his leg was taken by Surgeon J.M. Farley, 84th New York Infantry. His gravesite is on Findagrave. His picture from a photograph at the NY State Military Museum.
He married Ellen Murphy (d. 1914) and they had at least 4 children.
Grand Army of the Republic (GAR) Post #65 in Oswego was named for him.
04/23/1873; Oswego, NY; burial in Saint Paul Cemetery, Oswego, NY
1 State of New York, Adjutant-General, Annual Report of the Adjutant General of the State of New York [year]: Registers of the [units], 43 Volumes, Albany: James B. Lyon, State Printer, 1893-1905, For the Year 1899, Ser. No. 20, pg. 625 [AotW citation 6219]
2 Barnes, Joseph K., and US Army, Office of the Surgeon General, The Medical and Surgical History of the War of the Rebellion, 6 books, Washington DC: US Government Printing Office, 1870, Volume 2, Part 3, pg. 232 [AotW citation 26135]