STL is the airport code for the Lambert-St. Louis International Airport, which is located about 10 miles from downtown St. Louis, Missouri. As of 2015, the address is 10701 Lambert International Blvd., St. Louis, MO 63145.
Commonly known as Lambert Field, the Lambert-St. Louis International Airport is the largest airport in Missouri. Serving over 12 million passengers a year, it is one of the 50 busiest airports in the United States. It serves as a hub for Southwest Airlines, features 12 other airlines and provides hundreds of flights to destinations throughout the United States and Canada, as well as to Mexico and the Caribbean.