You’re staring at a map of the United States, tracing that thick blue line that cuts right through the heart of the country. It looks like a straight shot. A simple concrete ribbon. But if you’re wondering how long is Interstate 70, you aren't just looking for a single number. You’re looking at 2,150 miles of asphalt, give or take a few tenths depending on which exit ramp you accidentally overshoot in St. Louis.
I've driven large chunks of this road. It's weird. One minute you are dodging potholes in Baltimore and the next you’re staring at the sheer, terrifying rock walls of the Glenwood Canyon in Colorado. It’s a massive engineering feat that stretches from the East Coast all the way to the middle of a desert in Utah.
Most people think interstates have to go coast-to-coast to be "major." I-70 doesn't. It just... stops.
Breaking Down the 2,150-Mile Journey
The Federal Highway Administration (FHWA) pegs the official length at approximately 2,151 miles. If you want to be pedantic, the official 2020 route log lists it at 2,150.89 miles. That makes it the fifth-longest east-west interstate in the country. It trails behind I-90, I-80, I-40, and I-10.
Think about that distance.
If you drove a steady 70 miles per hour without stopping for gas, beef jerky, or a nap, it would take you nearly 31 hours to finish the trip. But nobody does that. You’ve got the Appalachian Mountains, the Great Plains, and the Rockies to deal with. The length isn't just a horizontal measurement; it’s a vertical one too. You start at sea level in Maryland and eventually find yourself at 11,158 feet when you pass through the Eisenhower Memorial Tunnel.
That tunnel is a beast. It’s the highest point on the entire Interstate Highway System.
Why the Length of Interstate 70 Starts in a Parking Lot
Here is a fun bit of trivia that most people miss: I-70 starts (or ends, depending on your direction) in a bit of a whimper. On the eastern side, it doesn't actually hit the Atlantic Ocean. It begins at a park-and-ride lot in Baltimore, Maryland. Specifically, it terminates at a junction with I-695. There were original plans to take it all the way into the heart of the city, but local protests over neighborhood destruction killed that dream.
So, it just stops.
On the western end, it’s even more isolated. You’d think a road this big would end in a major city like Los Angeles or San Francisco. Nope. It ends at a junction with I-15 near Cove Fort, Utah. If you reach the end of I-70 heading west, you’re basically in the middle of a beautiful, barren wilderness. There is a famous stretch in Utah between Green River and Salina where there are no services—no gas, no water, no nothing—for over 100 miles.
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It is the longest stretch of interstate in the U.S. without any motorist services.
The State-by-State Mileage Split
If you’re planning a cross-country move or a really long road trip, knowing how the miles are distributed helps. Every state handles their segment of I-70 differently.
- Maryland: A mere 91 miles. It’s a quick blip.
- Pennsylvania: About 167 miles. Warning: you have to jump on the PA Turnpike for part of this, which means paying a toll to stay on a road you thought was free.
- West Virginia: The "blink and you'll miss it" state. Only 14 miles.
- Ohio: 225 miles. This is where you settle into the long, flat rhythm of the Midwest.
- Indiana: 156 miles. Straight through Indianapolis.
- Illinois: 155 miles.
- Missouri: 250 miles. St. Louis to Kansas City is a classic drive, but the traffic near the stadiums can be a nightmare.
- Kansas: 424 miles. This is the big one. People complain about Kansas being boring, but there is a strange beauty in the Flint Hills.
- Colorado: 451 miles. This is the longest segment in any single state. It's also the most beautiful and the most stressful for your car's brakes.
- Utah: 231 miles. Desolate and gorgeous.
The "First Interstate" Debate
When talking about how long is Interstate 70, history buffs usually start arguing about where it actually began. Missouri claims they were the first to start paving under the Federal-Aid Highway Act of 1956. They’ve even got signs saying so. However, Kansas claims they were the first to complete a section of interstate paved with concrete.
It’s a bit of a sibling rivalry between the two states.
Regardless of who laid the first brick, the road changed everything. Before I-70, crossing the Rockies meant winding through dangerous mountain passes on two-lane roads. Now, you’ve got a multi-lane highway, though "dangerous" is still a fair word for it during a February snowstorm.
The construction of the segment through Glenwood Canyon in Colorado was actually one of the last pieces of the original interstate system to be finished. It didn't open until 1992. It cost about $490 million for just 12 miles of road because they had to build it into the side of a cliff without destroying the environment.
Real-World Advice for the Long Haul
If you are actually going to drive the full length of I-70, don't trust your GPS blindly when it comes to time.
In Kansas, the wind can be so strong it knocks your gas mileage down by 5 miles per gallon. In Colorado, the "I-70 mountain corridor" is notorious for "pacing," where the police hold up traffic to prevent gridlock during ski season. You might see a sign saying it’s 60 miles to Vail, but that could easily take three hours if the Eisenhower Tunnel has a "metering" light on.
Also, watch your fuel in Utah.
The signs that say "No Services for 100 Miles" are not joking. They aren't trying to be dramatic. If you have a quarter tank of gas left in Green River, you will run out of fuel in the middle of the San Rafael Swell. Cell service is spotty at best there.
Key Takeaways for Your Trip
- Check your brakes. If you’re heading west into Colorado, the descent from the Continental Divide is brutal. Use your engine to slow down, not just your brake pedal.
- Tolls exist. You'll hit them in Pennsylvania and potentially around Kansas City depending on which bypass you take.
- The Missouri bottleneck. The bridge over the Missouri River at Rocheport used to be a massive headache, though recent construction has cleared things up significantly.
- The Kansas stretch. Use it to make time. The speed limit is 75 mph for most of it, and it's mostly flat.
Actionable Steps for Navigating I-70
To make the most of this 2,150-mile monster, you need more than just a full tank of gas.
- Download Offline Maps: Especially for the Utah stretch and the remote parts of the Colorado Rockies. Your data will drop.
- Monitor the COtrip App: If you’re in Colorado, this is the only way to know if a rockslide or snowstorm has closed the canyon.
- Time Your Cities: Try to hit Columbus, Indianapolis, and St. Louis outside of the 7:00 AM to 9:00 AM window. These cities use I-70 as a primary commuter artery, and the congestion is real.
- Check the Weather Vertically: Don't just look at the temperature in Denver. Check the temperature at the Eisenhower Tunnel. It can be 60 degrees in the city and a blizzard at the pass.
Interstate 70 is a massive, sprawling piece of American history. It isn't just a way to get from Maryland to Utah; it's a cross-section of the entire country's geography. Whether you're driving the whole thing or just a segment, respect the mountains, fear the Utah desert, and keep an eye on your odometer.