A national secondary road (Irish: Bóthar Náisiúnta den Dara Grád) is a category of road in Ireland. These roads form an important part of the national route network but are secondary to the main arterial routes which are classified as national primary roads. National secondary roads are designated with route numbers higher than those used for primary roads, but with the same "N" prefix. Routes N51 and higher are all national secondary roads. The former N8 bypass of Mitchelstown was re-classified as the N73 when the Fermoy (Moorepark) to Kilbehenny section of the M8 was completed.