The A4200 is a major thoroughfare in central London. It runs between the A4 at Aldwych, to the A400 Hampstead Road/Camden High Street, at Mornington Crescent tube station, via Holborn, Bloomsbury, Euston and Somerstown.

Aldwych is a street and the name of the area immediately surrounding it, in the City of Westminster, part of Greater London, and is part of the West End Theatreland. The 450 metres (1,480 ft) street starts 600 metres (2,000 ft) east-northeast of Charing Cross, the conventional map centre-point of the capital city.