Dulles International Airport

Built on nearly 12,000 acres straddling the Loudoun and Fairfax county line, Dulles International Airport opened on Nov. 19, 1962, and is now the fifth-busiest airport in the country. The airport serves about 24 million passengers each year and is the anchor in the Dulles corridor — a region that has attracted numerous high-tech businesses, especially along the Dulles Toll Road. More than $3 billion will go toward building two additional levels at the airport, which should be complete by the end of 2009. The airport has several improvement projects in the works to accommodate future growth.