Matthew O'Conor (Irish: Mathghamhain Ó Conchubhair; 1773–1844) of Mount Druid House, Ballinagare, County Roscommon, Ireland was an Irish historian, Landowner from the O'Conor family, Barrister and de jure King of Connacht.
Matthew was educated for the priesthood in Rome, but changed his mind and became by profession a lawyer.
[1] Matthew was highly regarded by fellow Irish scholars such as George Petrie and John O'Donovan.
To the latter he gave unstinting aid during his field work in Roscommon for the Ordnance Survey; O'Donovan held him in very high regard, not only because of his historical efforts and political work, but also because of his noble descent and status as a Prince of the Royal Family of Connacht.
He wrote The History of Irish Catholics from the Settlement in 1691, based on letters of his grandfather Charles O’Conor to Dr. John Curry.