The M2 is a motorway in Belfast and County Antrim in Northern Ireland. It is in two sections, the southern section running from north Belfast to Antrim and the northern section acts as a bypass of Ballymena, with the A26 road linking the two sections. In total it is 22 miles (36.2 kilometres). The M2 has the busiest sections of any road or motorway in Northern Ireland. The M2 is one of Northern Ireland's most important motorways, forming most of the main route from Belfast city to both Belfast International Airport and less than a quarter of the way to Derry. It forms part of the unsigned European route E01, E16 and E18 roads.