High Quality Content by WIKIPEDIA articles! Lambert-St. Louis International Airport (IATA: STL, ICAO: KSTL, FAA LID: STL) is a Class B international airport serving Greater St. Louis. It is located approximately 10 miles (16 km) northwest of downtown St. Louis in unincorporated St. Louis County between Berkeley and Bridgeton. It is the largest and busiest airport in the state with 250 daily departures to more than 88 domestic and international locations. In 2010 12.3 million passengers traveled through the airport.