Piccadilly (/ˌpɪkəˈdɪlɪ/) is a road in the City of Westminster, London to the south of Mayfair, running from Hyde Park Corner in the west to Piccadilly Circus in the east. It forms part of the A4 route, which connects central London to Hammersmith, Earl's Court, Heathrow Airport and the M4 westward. The area of St. James's lies to the south of the eastern section of the street, while the western section is built up only on the northern side.