The A40 is a trunk road in England and Wales, connecting London to Fishguard. It is one of the few remaining of the "old" trunk routes not to have been superseded by a direct motorway link, though some parts, such as the southern section from London to Oxford are served by the M40.

The route passes through the following places in order:

• London - the A40 is the Westway, the main route out of London to the north-west.
• Ruislip
• Denham
• Gerrard's Cross
• Beaconsfield
• High Wycombe
• West Wycombe
• Stokenchurch
• Oxford
• Eynsham
• Witney
• Burford
• Northleach
• Charlton Kings
• Cheltenham
• Gloucester
• Highnam
• Huntley
• Ross-on-Wye
• Whitchurch
• Monmouth
• Abergavenny
• Brecon
• Llandovery
• Llandeilo
• Carmarthen
• St Clears
• Haverfordwest
• Fishguard

See also

• British road numbering scheme