8 Incredibly Long U.S. Interstates That Seem To Go On Forever

Think you’ve got the road trip stamina to tackle America’s longest highways? The U.S. interstate system isn’t just a network of roads—it’s a web of epic journeys waiting to happen. These concrete veins run through remote plains, bustling cities, and jaw-dropping natural landscapes.

Ever wondered what it’s like to drive non-stop from the Atlantic to the Pacific? Or cruise a highway that feels like it’ll never end? Some of these routes stretch for thousands of miles, crossing multiple time zones and packing a serious punch of Americana along the way.

So, gas up, grab your favorite snacks, and let’s dive into the longest interstates in the U.S.—because adventure doesn’t always need a boarding pass.

1. I-90: The Northern Backbone

Stretching a whopping 3,020 miles from Seattle to Boston, I-90 holds the crown as America’s longest interstate highway. The journey takes you through 13 states, passing spectacular mountain ranges like the Cascades and Rockies before rolling through the Great Plains.

During winter months, sections through the mountains can transform into treacherous snow-covered passages that challenge even the most experienced drivers. I’ve driven portions through Montana where the road seems to melt into the horizon, creating an almost hypnotic effect.

My favorite stretch runs through South Dakota’s Black Hills, where the interstate provides easy access to Mount Rushmore and Badlands National Park.

2. I-80: The Historic Cross-Country Route

Following roughly the same path as the historic Lincoln Highway, I-80 spans 2,899 miles from San Francisco to Teaneck, New Jersey. This legendary route takes travelers through major cities like Salt Lake City, Omaha, and Chicago while connecting the Bay Area to the New York metropolitan region.

When driving across Nevada on I-80, you’ll experience some of the most isolated stretches of interstate in America. The highway climbs to its highest point at Sherman Summit in Wyoming, reaching an elevation of 8,640 feet above sea level.

Did you know I-80 closely parallels the first transcontinental railroad and the Pony Express route? History buffs will appreciate the numerous historical markers along this significant corridor.

3. I-40: The Southern Corridor

If you’re yearning for a journey through America’s Southwest, I-40’s 2,555-mile path from Barstow, California to Wilmington, North Carolina delivers spectacular desert vistas and Southern charm. The highway roughly follows the historic Route 66 through states like Arizona, New Mexico, and Oklahoma.

Arizona’s section offers some of the most breathtaking scenery, with the painted desert and petrified forest just a short detour away. I remember driving through Albuquerque where the Sandia Mountains create a stunning backdrop to the highway.

Truckers consider I-40 one of the nation’s most important freight corridors. Next time you’re traveling this route, notice how the landscape transforms from arid desert to lush greenery as you head eastward.

4. I-10: The Southernmost Coast-to-Coast Highway

Hugging America’s southern edge, I-10 extends 2,460 miles from Santa Monica, California to Jacksonville, Florida. This sun-drenched interstate crosses eight states and passes through major cities like Phoenix, San Antonio, Houston, and New Orleans.

The stretch through southern Texas seems particularly endless, with miles of flat terrain that tests your endurance. When crossing Louisiana, the highway transforms into one of the longest bridges in the world – the Atchafalaya Basin Bridge stretches nearly 18.2 miles! Though challenging at times, I-10 rewards travelers with incredible diversity.

You’ll experience everything from the stark beauty of the Sonoran Desert to the lush wetlands of Florida, making it a true American adventure.

5. I-75: The Great Lakes to Gulf Highway

Connecting the Great Lakes to the Gulf of Mexico, I-75 stretches 1,786 miles from Sault Ste. Marie, Michigan to Miami, Florida. This north-south corridor serves as a major vacation route for northerners seeking Florida sunshine during winter months.

While driving through Kentucky, you’ll encounter the “Kentucky Thoroughbred Country” with its picturesque horse farms visible from the highway. The interstate also passes through Atlanta, which serves as a major transportation hub for the Southeast.

Where I-75 crosses into Florida, you’ll find the official welcome center offering free orange juice – a tradition since 1949! This small gesture perfectly captures the hospitality you’ll encounter along this lengthy route that connects two vastly different American regions.

6. I-95: The Eastern Seaboard Lifeline

Running parallel to the Atlantic coast, I-95 connects Miami, Florida to Houlton, Maine over its 1,908-mile course. This crucial artery serves the densely populated Eastern Seaboard, passing through more states (15) than any other interstate.

Traffic can be notoriously heavy around major metropolitan areas like Washington D.C., New York, and Boston. However, the northern sections through Maine offer peaceful drives through pine forests that contrast sharply with the urban congestion.

I’ve always found the Delaware Memorial Bridge crossing particularly striking – it’s one of many impressive bridges along I-95. The highway serves approximately 110 million people, or about 35% of America’s population, making it perhaps the most economically vital interstate in the system.

7. I-70: The Mid-America Connection

Starting in the remote town of Cove Fort, Utah and ending in Baltimore, Maryland, I-70 spans 2,153 miles across America’s heartland. This impressive highway tunnels through the Rocky Mountains via the Eisenhower-Johnson Memorial Tunnel – the highest point in the Interstate System at 11,158 feet.

Kansas offers perhaps the straightest section of interstate anywhere in America. For nearly 424 miles, the highway barely curves as it crosses the state’s prairie landscape. Many drivers find this stretch mesmerizing or monotonous, depending on their perspective.

My most memorable experience on I-70 was driving through Colorado’s Glenwood Canyon, where engineers performed an incredible feat by squeezing the highway alongside the Colorado River through steep canyon walls.

8. I-35: The NAFTA Superhighway

Often called the “NAFTA Superhighway,” I-35 runs 1,568 miles from Laredo, Texas at the Mexican border to Duluth, Minnesota near Canada. This vital north-south route serves as a crucial corridor for international trade, with thousands of trucks crossing daily.

The highway splits into eastern and western branches in the Dallas-Fort Worth area before reuniting in Denton, Texas. Kansas City marks another split, with I-35 dividing into I-35E and I-35W through Minneapolis and St. Paul. When driving through Oklahoma City, you’ll notice the highway dips below ground level through downtown – a design feature that preserves the city’s street grid.

Though not the longest interstate, I-35’s economic importance can’t be overstated as it connects three nations’ trade networks.