BWI Airport station is a train station located in an unincorporated area within Anne Arundel County, Maryland. It is served by Amtrak intercity services and MARC Penn Line regional rail service. The station is located on the airport complex just over a mile from the main terminal of Baltimore-Washington International Thurgood Marshall Airport. A free shuttle bus runs between the station and the airport terminal every 6 minutes from 5 am to 1 am and every 25 minutes from 1 am to 5 am.