Castleblayney (Baile na Lorgan in Irish) is a town in County Monaghan, Ireland. It is on the N2 National Primary Route from Dublin to Derry, near the border with Armagh, Northern Ireland. The town lies on the shore of Lough Muckno , the largest lake in Co. Monaghan.
The town is named for Sir Edward Blayney, who received a grant of land here from James I. Hope Castle, also known as Blayney Castle, is a large 19th-century house near the town and was previously owned by the same Hope family after which the Hope Diamond is named.
