Baltimore/Washington International Thurgood Marshall Airport (IATA: BWI, ICAO: KBWI, FAA LID: BWI) is an international commercial airport serving the Baltimore-Washington Metropolitan Area in the United States. It is commonly called BWI, BWI Airport or BWI Marshall, BWI being an initialism for "Baltimore/Washington International" and the facility's IATA Airport Code. The airport is located in Linthicum, Maryland, a census-designated place in northern unincorporated Anne Arundel County, about 10 miles (16 km) south of Baltimore and 30 miles (48 km) northeast of Washington, D.C. It is named after Thurgood Marshall, a Baltimore native and the first African American to serve on the Supreme Court of the United States. BWI is a focus city for Southwest Airlines and a secondary hub for AirTran Airways. 20.49 million passengers passed through BWI in 2008, down 2.6% from 2007's record 21.04 million, making it the United States' 24th busiest airport.