Denver International Airport, DEN, often referred to as DIA, is an airport in Denver, Colorado. At 53 square miles (140 km2) it is the largest airport in the United States by total area, and the second largest airport in the world after King Fahd International Airport. Runway 16R/34L is the longest public use runway in the United States. In 2011 Denver International Airport was the 11th-busiest airport in the world by passenger traffic with 52,699,298 passengers.
It was the fifth-busiest airport in the world by aircraft movements with over 635,000 movements in 2010. The airport is in northeastern Denver, Colorado, and is operated by the City & County of Denver Department of Aviation. Denver International Airport was the busiest and largest airport in the United States without non-stop service to Asia, until United Airlines announced non-stop service to Tokyo's Narita Airport, commencing on March 31, 2013. DIA was voted Best Airport in North America by readers of Business Traveler Magazine six years in a row (2005–2010) and was named "America's Best Run Airport" by Time Magazine in 2002.
Denver International Airport is the main hub for low-cost carrier Frontier Airlines and commuter carrier Great Lakes Airlines. It is also the fourth-largest hub for United Airlines. The airport is a focus city for Southwest Airlines. Since commencing service to Denver in January 2006, Southwest has added over 40 destinations, making Denver its fastest-growing market. Denver International Airport is the only airport in the United States to have implemented an ISO 14001-certified environmental management system covering the entire airport.