The R665 road is a regional road in Ireland. The route runs from Mitchelstown to Clonmel via Ballyporeen, Clogheen and Ardfinnan, passing through parts of counties Cork, Tipperary and Waterford. The R665 was once a key part of the historic route from Dublin to Cork and was mapped as such as late as 1778. A turnpike road, it was also a key part of the route linking Mallow with Dublin, via today's N73.Taylor and Skinner, Maps of the Roads of Ireland (Dublin, 1778)
See also Roads in Ireland Motorways in the Republic of Ireland National secondary road Trunk roads in Ireland History of roads in Ireland
References
Roads Act 1993 (Classification of Regional Roads) Order 2006 – Department of Transport