A regional road in the Republic of Ireland is a class of road not forming a major route, but nevertheless forming a link in the national route network. There are over 11,600 kilometres of regional roads. Regional roads are numbered with three-digit route numbers, prefixed by "R". The equivalent road category in Northern Ireland are B roads.

A national primary road is a road classification in Ireland. National primary roads form the major routes between the major urban centres. There are 2649 km of national primary roads. This category of road has the prefix "N" followed by one or two digits. Motorways are prefixed "M" followed by one or two digits.