What is Colorado DIA?
Colorado DIA — Denver International Airport — is the principal airport serving the state of Colorado and the Rocky Mountain region. Often shortened to "DIA" by locals (a holdover from its 1995 opening) or referred to by its three-letter IATA code DEN, it is operated by the City and County of Denver and sits on roughly 33,500 acres — making it the second-largest airport in the world by total land area.
In 2024 DIA handled more than 77 million passengers, making it the 4th-busiest airport in the United States and one of the 20 busiest in the world by passenger volume. United Airlines, Southwest Airlines, and Frontier all use DIA as a major hub.
Colorado DIA at a glance
| Official name | Denver International Airport |
| IATA code | DEN |
| ICAO code | KDEN |
| Nickname | DIA |
| Address | 8500 Peña Blvd, Denver, CO 80249 |
| Distance from downtown Denver | ~25 miles (40 km) NE |
| Opened | February 28, 1995 |
| Acreage | ~33,500 acres (largest in the U.S.) |
| 2024 passenger volume | 77+ million (4th busiest in U.S.) |
| Operator | City and County of Denver |
Is DIA in Denver or Aurora, Colorado?
DIA is technically within the City and County of Denver, though the surrounding land — where most off-airport parking lots, hotels, and rental car facilities operate — is in Aurora, Colorado. Denver annexed the airport property in 1989 specifically to enable its construction. Today the airport feels closer to Aurora than to central Denver, but its mailing address and jurisdiction are Denver, CO.
Parking at Colorado DIA
DIA offers three on-airport parking categories plus a private off-airport market in Aurora. Rates effective May 14, 2025:
- 61st & Peña Lot — $8/day. Cheapest on-airport option, requires the RTD A-Line train (no car shuttle).
- Pikes Peak & Longs Peak Economy Lots — $10/day. On-airport shuttle lots with free shuttle every 7–10 minutes.
- Mt. Elbert Lot — $15/day. Closer-in on-airport shuttle lot.
- Covered Terminal Garage — $35/day ($7/hr, first 30 min free). Connected directly to Jeppesen Terminal.
- DIA Valet — $40–$50/day. Drop your car at the terminal curb.
- Off-airport lots — from $9/day. Canopy, Park2Jet, Fine Airport Parking, ParkDIA, WallyPark, The Parking Spot, USAirport Parking — all include a free 24-hour shuttle.
See our complete DIA parking rates guide for full breakdowns by stay length, plus our cheapest parking at DIA roundup.
Getting to Colorado DIA
From anywhere in Colorado, the main routes to DIA all funnel onto Peña Boulevard, the airport's only road access. Common approaches:
- From downtown Denver: I-70 east to Peña Blvd north — 25 miles, 30–40 min.
- From Boulder: US-36 east to I-270 east to I-70 east to Peña Blvd — 45 miles, ~55 min.
- From Colorado Springs: I-25 north to E-470 east to Peña Blvd — 80 miles, ~90 min.
- From Fort Collins: I-25 south to E-470 east to Peña Blvd — 75 miles, ~85 min.
- From the mountains (I-70 west): I-70 east directly to Peña Blvd — drive time varies with ski traffic.
- RTD A-Line train: Union Station to DIA in 37 minutes, $10.50 one-way.
For block-by-block directions from every direction, see our directions to DIA page.
Why DIA matters to Colorado travelers
For Colorado residents, DIA is the gateway for nearly all out-of-state and international travel. The state has smaller commercial airports — Colorado Springs (COS), Grand Junction (GJT), Aspen (ASE), Eagle/Vail (EGE), and Durango (DRO) — but DIA dwarfs them in both passenger volume and number of nonstop destinations. Anyone flying internationally from Colorado almost certainly connects through DIA.
That centrality is also why DIA parking gets so much attention. With travelers driving in from every corner of the state, parking demand stays high year-round, peaking dramatically during ski season (December–March), summer (June–August), and the major holidays. Booking off-airport parking in advance saves both money and time during these windows.
Frequently asked questions — Colorado DIA
Why is it called DIA when the code is DEN?
DIA stands for Denver International Airport (the full name). DEN is the three-letter IATA code used by airlines, baggage tags, and reservation systems. The airport opened in 1995 and locals continued using DIA from the marketing era, while the airline industry uses DEN globally.
What city is DIA in?
Denver, Colorado, ZIP 80249. The airport is within Denver city limits, but the surrounding business district (hotels, parking lots, rental car facilities) is technically in Aurora, CO.
How big is Colorado's DIA?
DIA covers roughly 33,500 acres (52.4 square miles) — the largest airport in the United States and the second-largest in the world by total land area. The terminal complex itself is much smaller; most of the acreage is buffer land and future expansion.
What airlines fly out of DIA?
Major DIA carriers include United Airlines (hub), Southwest Airlines (hub), Frontier Airlines (hub), Delta, American, Alaska, JetBlue, Spirit, and several international carriers. United is the largest, with the most nonstop destinations.
Can I park at DIA without a reservation?
Yes — all on-airport lots (Economy, garage, valet) accept drive-up parking, although Economy lots can fill on peak days. Off-airport lots also accept drive-ups but online booking saves 15–30% vs walk-up rates. See our no reservation parking guide.