Piccadilly is a road in the City of Westminster, London, England, to the south of Mayfair, between Hyde Park Corner in the west and Piccadilly Circus in the east. It is part of the A4 road that connects central London to Hammersmith, Earl's Court, Heathrow Airport and the M4 motorway westward. St James's is to the south of the eastern section, while the western section is built up only on the northern side. Piccadilly is just under 1 mile (1.6 km) in length, and it is one of the widest and straightest streets in central London.