From The Airport Wiki

London Stansted Airport (IATA: STN, ICAO: EGSS) is a large passenger airport with a single runway and hub for a number of major European low-cost airlines. It is located in the Uttlesford District of the English county of Essex about 30 miles (48 km) north-east of London. It is about 2 miles (3 km) outside Bishop's Stortford and 6 miles (10 km) outside Harlow. It is the third largest airport serving the London area after Heathrow and Gatwick; and is one of London's five international airports along with Luton and London City Airports.