Denver International Airport (IATA: DEN, ICAO: KDEN, FAA LID: DEN), often referred to as DIA, is an airport inDenver, Colorado, United States. At 34,000 acres (53 sq mi), it is the largest airport in the United States by total land area.[4] Runway 16R/34L, with a length of 16,000 feet (4,877 m), is the longest public use runway in the United States. As of 2014, DIA was the 18th-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 connection network in the country. 141 gates spread out over three detached, yet internally connected, concourses (A, B & C) helps to organize the high volume of passenger traffic.DIA has non-stop service to destinations throughout North America, Latin America, Europe and Asia. The airport is in northeastern Denver and is operated by the City & County of Denver Department of Aviation. DIA was voted Best Airport in North America by readers of Business Traveler Magazine six years in a row (2005–2010)[5] and was named "America's Best Run Airport" by Time Magazine in 2002.[6]The airport is the main hub for Frontier Airlines and Great Lakes Airlines. It is also the fourth-largest hub for United Airlines with 375 daily departures to 141 destinations. Within the past decade DIA has become a major focus city forSouthwest Airlines. Since commencing service to Denver in January 2006, Southwest has added nearly 60 destinations with 190 daily departures making Denver its fastest-growing market and 4th most utilized airport.DIA is the only airport in the United States to have implemented an ISO 14001-certified environmental management system covering the entire airport.[7]