Hi Robert,
there wsa a small military barracks in Mitchelstown, built in 1823 and burned during the Civil War in 1922. You will find details of historic sites in Mitchelstown, with accompanying map if you Google 'map of Mitchelstown' and can see where that barracks was located. This is the link on Google that will lead to that map etc: 09_mitchelstown-cork-ireland-historic-map-brochure.pdf
There was a much larger barracks in Fermoy, the neighbouring town, but if the birth record states 'Brigown', then it is Mitchelstown it refers to.
The following info on Rev. Graves I also found on Google search:
Rev Dr Richard Hastings "Rector at Brigown, County Cork, Ireland" Graves DD
Born about 1791 in Irelandmap
ANCESTORS
Son of Richard Graves DD and Eliza (Drought) Graves
Brother of Elizabeth Maria (Graves) Burton, Jane (Graves) Macdonnell, Robert James Graves, Anna (Graves) Mayne and Harriet (Graves) Brinkley
Died 25 Dec 1877 at about age 86 in Dublin,
Biography
Church of Ireland Clergy
Clergyman, Doctor of Divinity
Rector of Brigown, Co Cork, Ireland
He was the second son and third child (of 10) of The Very Reverend Richard Graves, Dean of Ardagh, and Elizabeth Mary {Drought} Graves, his wife
He entered Trinity College Dublin on 1 June 1807, aged 16. B.A. 1812, M.A. 1815, B.D. and D.D. 1828. [1]
He was ordained in 1814. In 1823 he became Curate Ballymoyer, Armagh and from 1830 to 1832 he was Rector and Vicar of Ardskeagh, Cloyne.
He was collated to the Prebendary of Brigown on 30 July 1832. He was also Rector of the Church of Ireland Parish church at Brigown, at the top of George Street, Mitchelstown, in the Diocese of Cloyne, County Cork, Ireland
Author of: "Comparative Analysis of The Three Seven-Headed Ten-Horned Symbols, Revelation Chapters XII, XIII, XVII, containing An Explanation of the So-Called Enigma Chap. XVII, 9-11; Strictures on Faber's Napoleonic Theory and Elliott's Theory of An Eight-Headed Beast; and some Thoughts on The Approaching Doom of Papal Babylon", London 1869
Author of: "Daniel's Great Period 2300 Days Determined"; and "Daniel's Terminal Synchronism Discovered"
Biographer of the late Dean Graves [his father], and editor of the Dean's 'Whole Works'. Background family information appears in the section 'Memoir of Dean Graves' in Vol 1. [2]
He died in 1877. [3]
Death Notice - Newry Reporter December 29, 1877
Graves —December 25, at his residence, 31 Raglan Road, Dublin, the Rev. Richard Hastings Graves, D.D., late rector of Brigown, Co. Cork, aged 86 years.
I hope the above may be of help/interest to you.
Best wishes,
Anne Griffin