What is the airport code for Denver, Colorado?

The airport code for Denver, Colorado, is DEN, which stands for Denver International Airport. This three-letter code is part of the International Civil Aviation Organization (ICAO) system, which assigns unique identifiers to airports around the world. The choice of DEN is derived from the city's name, which helps to easily identify the location of the airport.

The other options refer to different airports: RNO is the airport code for Reno, Nevada; RIC is the airport code for Richmond, Virginia; and FCO designates Leonardo da Vinci International Airport in Rome, Italy. Each code is unique and reflects the location of different airports, highlighting why DEN is the correct answer for Denver.