The A5 is a major road in the United Kingdom. It runs from London to Holyhead, on the Isle of Anglesey in Wales, following in part the route of the Roman Watling Street.
Starting at Marble Arch, it runs north west up the Edgware Road. The A5 as numbered disappears near Edgware, but re-emerges south of Luton. However, the road itself continues as the A5183 from Edgware to Elstree, Borehamwood, Radlett, St Albans and Redbourn, to junction 9 of the M1, where it becomes numbered as the A5 again. It then travels through Dunstable, Milton Keynes and Towcester, near Rugby and Hinckley, then through Tamworth, Cannock and Telford. After bypassing Shrewsbury and Oswestry, it enters Wales and continues through Llangollen and Betws-y-Coed. The road then crosses the Menai Strait near Bangor before arriving at the port of Holyhead.
There is also an A5 road in Northern Ireland. It runs from Derry south, via Strabane and Omagh, to join the N2 road at the border with the Republic of Ireland.