Denver International Airport (IATA: DEN, ICAO: KDEN, FAA LID: DEN), often referred to as DIA, is an airport in Denver, Colorado. At 34,000 acres (53 sq mi), it is the largest airport in the United States by total area. Runway 16R/34L is the longest public use runway in the United States. As of 2015, DIA was the 15th-busiest airport in the world and the 5th busiest in the United States by passenger traffic with over 53 million passengers. It also has the third largest domestic network.