Denver International Airport
Denver International Airport, often referred to by locals as DIA, is an international airport in the Western United States, primarily serving metropolitan Denver, Colorado, as well as the greater Front Range Urban Corridor.
Runway 16R/34L, with a length of, is the longest public use runway in North America and the fifth longest on Earth. The airport is driving distance northeast of Downtown Denver, farther than the former Stapleton International Airport which DEN replaced; the airport is actually closer to the City of Aurora than central Denver, and many airport-related services, such as hotels, are located in Aurora.
Opened on February 28, 1995, DEN serves 27 airlines providing nonstop service to 230 destinations throughout the Americas, Europe, and Asia; it was the fourth airport in the United States to exceed 200 destinations. The airport has been the largest operating hub for Frontier Airlines and Southwest Airlines for several years and, as of 2024, DEN has eclipsed Chicago's O'Hare International Airport as the largest operating hub for United Airlines as well. The Colorado Department of Transportation's 2025 Economic Impact Study estimated that the airport contributes $47.2 billion annually to Colorado's economy and, with over 40,000 employees, the airport is the largest employer in the state of Colorado. The airport is located on the western edge of the Great Plains and within sight of the Front Range of the Rocky Mountains.
In 2021 and 2022, DEN was the third busiest airport in the world as well as the third busiest airport in the United States by passenger traffic. In 2023, it was the sixth busiest airport in the world and remained the third busiest in the United States, having served around 77.8 million passengers, more than a 12% increase from the prior year. DEN has been among the top 20 busiest airports in the world and top 10 busiest airports in the United States every year since 2000.
In 2025, DEN set an all-time passenger record with 82,427,962 passengers served, up 0.1% over the previous record set in 2024.
History
has traditionally been home to one of the busier airports in the United States because its midcontinent location was ideal for an airline hub. Several airlines, notably United Airlines and Continental Airlines, had hubs at the former Stapleton International Airport, helping make it the sixth-busiest airport in the country by the 1960s. However, Stapleton had little room to add more flights and its runways were too close together, which led to long delays and nationwide travel disruptions in bad weather.From 1980 to 1983, the Denver Regional Council of Governments investigated areas for a new area airport north and east of Denver. Meanwhile, in 1983, Federico Peña was elected mayor of Denver, campaigning on a plan to expand Stapleton onto Rocky Mountain Arsenal lands. The plan had broad support, but leaders in nearby Adams County threatened to sue over noise concerns.
Eventually Peña struck a deal: Adams County leaders would rally citizens to back a plan for Denver to annex of the county to build an airport away from established neighborhoods. In 1988, Adams County voters approved the annexation. The proposal was met with some skepticism because of its location: from the heart of the city. But seeing the importance of a Denver air hub to the national transportation system, the federal government put $500 million toward the new airport. The rest of the cost would be financed by bonds, to be repaid with fees on airlines. Ground was broken in September 1989.
Two years later, Mayor Wellington Webb inherited the megaproject, which at that time was scheduled to open on October 29, 1993. At the time United was refusing to move to the new airport over the high proposed fees. The airline finally relented under the condition that the airport include an automated baggage system.
Construction delays pushed opening day back, first to December 1993, then to March 1994. By September 1993, delays due to a millwright strike and other events meant opening day was pushed back again to May 1994.
In April 1994, the city invited reporters to observe the first test of the new automated baggage system. Reporters were treated to scenes of clothing and other personal effects scattered beneath the system's tracks and carts that would often toss the luggage right off the system. After the embarrassing preview, the mayor cancelled the planned May opening. The baggage system continued to be a maintenance hassle and was finally terminated in September 2005, with traditional baggage handlers manually handling cargo and passenger luggage.
DEN finally replaced Stapleton on February 28, 1995, 16 months behind schedule and at a cost of $4.8 billion, nearly $2 billion over budget. The construction employed 11,000 workers. United Airlines Flight 1062 to Kansas City International Airport was the first to depart DEN and United Flight 1474 from Colorado Springs Airport was the first to arrive at the new airport.
In September 2003, runway 16R/34L was added, the airport's sixth and at, it is longer than the other runways. Its length, exceeded by only six other runways in the world, allows fully laden Airbus A380s and Boeing 747-8s to take off in the hot and high conditions at the airport, which is roughly above sea level.
During a blizzard on March 17–19, 2003, the weight of heavy snow tore a hole in the terminal's white fabric roof, and over of snow on paved areas closed the airport and its main access road for almost two days, stranding several thousand people. Another blizzard on December 20–21, 2006, dumped over of snow in about 24 hours. The airport was closed for more than 45 hours, stranding thousands. Following this, the airport invested heavily in new snow-removal equipment that has led to a dramatic reduction in runway occupancy times to clear snow, down from an average of 45 minutes in 2006 to just 15 minutes. In 2020, the airport was awarded the Balchen/Post award, which is presented by the Northeast Chapter of the American Association of Airport Executives for the outstanding snow and ice removal operation during difficult winter conditions.
After shunning DEN for over a decade for its high fees, Southwest Airlines entered the airport in January 2006 with 13 daily flights. Southwest has since rapidly expanded and is now the airport's second-largest carrier after United.
On November 19, 2015, a Westin hotel was added to the airport and on April 22, 2016, DEN received commuter rail service to Denver Union Station with the opening of RTD's A Line.
On September 9, 2015, a political campaign was launched by Mayor Michael Hancock to radically expand commercial development at DEN, previously prohibited by intergovernmental agreement between Denver and Adams County. The changes to the agreement were approved by both Denver and Adams County voters in November 2015.
In 2018, work began on a major interior renovation and reconfiguration to the entire Jeppesen Terminal including the beginning phases of construction to relocate all TSA security checkpoints from the A-Bridge and Great Hall on Level 5 to Level 6 while simultaneously updating and consolidating airline ticket counters/check-in for all airlines. Eventually, both pre- and post-security gathering and leisure areas will be incorporated into the spaces where both expansive TSA security areas on Level 5 are currently located. The renovation and reconfiguration will bring back the original intent and use of the Great Hall as a large commons area for airport patrons and visitors to enjoy. In early February 2024, the first of two new security screening areas opened to the public and North Security closed permanently. In early August 2025, the new East Security, directly across the Great Hall from West, opened ahead of schedule and South Security closed permanently, officially moving all security to Level 6. Simultaneously, the A-Bridge, previously the location of a small security checkpoint, reopened, now serving as a post-security alternative to the train for passengers departing from A gates., the phased terminal project was expected to be completed by 2028; however, a 2025 press release shared that the project has been moving ahead of schedule and is now projected to be complete in 2027.
Additionally in 2018, work commenced on a major gate expansion to all three concourses with 12 new gates being added to A, 11 to B, and 16 to C, for a total of 39 new gates. Following the completion of the project in 2020, United Airlines made plans to lease 24 additional gates on both A and B, as well as build a new United Club in Concourse A and expand their existing clubs in B. Southwest Airlines leased 16 of the new gates in C bringing its total gate count at DEN to 40, which is SWA's largest gate count at any single airport. By November 2022, all new gates in A-West, B-West, B-East and C-East were in use. New retail and restaurant tenants continued to open through 2024, as well as new art that will be commissioned and installed through 2025. Additionally, all existing way-finding signs, flight information display systems and gate signs were replaced after 2017 matching what is found at the new gates and within the renovated portions of the terminal. When both the ongoing terminal and concourse projects are completed, the airport will be able to handle upwards of 100 million passengers per year.
On August 20, 2021, the airport experienced a mechanical failure of its train system that caused significant delays. In response, a request for information from the private sector was issued to analyze options to possibly supplement the train system in the future. By 2023, several companies proposed their ideas to transport passengers.
In 2022, a committee was formed to support efforts to establish flights between Denver and Africa. A public survey was conducted but results were not released and, to date, no direct flights to Africa have been established.
In August 2022, DEN broke ground on an additional gate expansion project that would bring a total of 14 ground-loaded/tarmac gates to the east end of Concourse A to be used solely for Frontier Airlines operations. Originally constructed in 2018 as temporary regional gates for United Airlines, this A-East wing was vacated by United earlier in 2022, making way for the renovation and expansion of the Frontier gates. It is intended to be removed once a more permanent A-East expansion occurs at an unknown future date. The renovated and expanded Concourse A-East wing officially opened summer 2024 and resulted in a gain of four gates for Frontier Airlines.
In December 2023 DEN started construction on a new 'Center of Equity and Excellence in Aviation' which will help under-served communities and prepare current and future employees for a career in aviation. The CEEA will be located directly below the Westin Hotel and DEN Plaza and is expected to open in late 2024 or early 2025.
In late 2023, the airport laid out preliminary plans to add four new concourses with 100 more gates east and west of the terminal by 2045. The project is being referred to as 'Operation 2045' and will help support the airport's goal of serving over 125 million passengers annually by that time.
On April 30, 2025, DEN welcomed the Airbus A380 for the first time for regular commercial service operated by Lufthansa. The aircraft arrived from Munich International Airport at 1:45 pm local time and departed back to Munich at 4:15 pm. Lufthansa ran daily A380 flights from DEN to Munich until September 30.