[15] Denver has traditionally been home to one of the busier airports in the United States because its midcontinent location was ideal for an airline hub.

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.

Meanwhile, in 1983, Federico Peña was elected mayor of Denver, campaigning on a plan to expand Stapleton onto Rocky Mountain Arsenal lands.

But seeing the importance of a Denver air hub to the national transportation system, the federal government put $500 million (equivalent to $1.1 billion as of 2023[update]) toward the new airport.

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 1 mi (1.6 km) above sea level.

[28] After shunning DEN for over a decade for its high fees, Southwest Airlines entered the airport in January 2006 with 13 daily flights.

[30] 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.

[31][32] 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 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.

[38] As of November 2022, all new gates in A-West, B-West, B-East and C-East are in use and new retail and restaurant tenants will continue to open through 2024 as well as new art commissioned and installed through 2025.

[40] In response, a request for information from the private sector was issued to analyze options to possibly supplement the train system in the future.

It is intended to be removed once a more permanent A-East expansion (similar to what recently opened in A-West) occurs at an unknown future date.

The renovated and expanded Concourse A-East wing officially opened summer 2024 and results in a gain of four gates for Frontier.

DEN is larger in land area (excluding water) than the US cities of Boston, Massachusetts and San Francisco, California.

DEN occupies the largest amount of commercial airport land area in North America, by a great extent.

In 2023, the airport announced a plan to significantly increase its passenger capacity by expanding the Jeppesen Terminal with additional check-in and TSA counters.

[50] The Jeppesen Terminal's internationally recognized peaked roof, designed by Fentress Bradburn Architects, resembles snow-capped mountains and evokes the early history of Colorado when Native American teepees were located across the Great Plains.

[52] Denver's public art program, which is financed by a mandatory 1% capital improvement budget, has resulted in a significant number of artworks being installed at the airport, where some can only be appreciated after passing through security.

Per Denver Public Art:[59]"Children of the World Dream of Peace" is a powerful mural expressing the artist's desire to abolish violence in society.

The mural then moves on to images of smiling children, dressed in traditional folk costumes from around the world, celebrating peace prevailing over war.

[62] Blue Mustang, by El Paso-born artist Luis Jiménez, was one of the earliest public art commissions for Denver International Airport in 1993.

RTD also operates an airport express bus service called skyRide between Arapahoe County or Boulder and DEN.

Amtrak offers a Fly-Rail plan for ticketing with United Airlines for trips into scenic areas in the Western U.S. via a Denver stopover.

A number of car rental companies are located at the airport, providing courtesy shuttle services from Jeppesen Terminal Level 5, Island 4, to their parking areas.

"[69] The airport suggests that cyclists who prefer a less-traveled route may use 56th Avenue to Valleyhead Road,[68] a rural 55-mph highway with no shoulder.

Conspiracies concerning the airport, inspired by the type of art, unusual architecture, and construction problems, started shortly after its completion.

[70][72] In 2019, an animatronic gargoyle named Gregoriden, or Greg for short, that randomly makes statements such as "welcome to Illuminati headquarters"[71] was installed.

In a marketing campaign that was tied to renovations started in 2018, posters were created with aliens joking that breeding grounds for gargoyles or meeting halls for Freemasons were being constructed.