Top 11 Longest Highways in the US (And Why They're Worth Every Mile)
- Rey Eleuterio
- 1 day ago
- 15 min read
Most people treat America's highways like a means to an end — just something to get through on the way to somewhere else. But if you've ever driven a long stretch of open road with nothing but sky ahead and miles behind you, you already know it can be so much more than that.
The US has one of the most extensive road networks in the world, and some of its highways stretch so far they cross a dozen states and just about every kind of landscape the country has to offer. Deserts. Mountains. Great Plains. Pacific coastline. New England forests. It's all out there, connected by asphalt.
Understanding the longest highway in the US isn't just trivia — it's a window into the history, geography, and sheer scale of this country. And once you know which roads are the longest, you start to realize just how many stories are sitting out there waiting for you, right off the next exit.
Key Takeaways
The longest highway in the US is US Route 20, a non-interstate highway that stretches roughly 3,365 miles from Newport, Oregon to Boston, Massachusetts. Among interstates specifically, I-90 takes the top spot at around 3,100 miles from Seattle to Boston. These aren't just long roads — they're cross-country journeys through some of America's most iconic landscapes. Whether you're a trucker, a road tripper, or just curious, knowing these routes helps you think bigger about what a drive across America could actually look like.
Highway | Miles | Direction | From → To | Notable States |
US Route 20 | ~3,365 | East–West | Newport, OR → Boston, MA | OR, ID, MT, WY, IA, OH, NY, MA |
US Route 6 | ~3,207 | East–West | Bishop, CA → Provincetown, MA | CA, NV, UT, CO, NE, IA, IL, PA, MA |
I-90 | ~3,100 | East–West | Seattle, WA → Boston, MA | WA, ID, MT, WY, SD, MN, WI, IL, IN, OH, PA, NY, MA |
US Route 30 | ~3,073 | East–West | Astoria, OR → Atlantic City, NJ | OR, ID, WY, NE, IA, IL, IN, OH, PA, NJ |
US Route 50 | ~3,011 | East–West | Sacramento, CA → Ocean City, MD | CA, NV, UT, CO, KS, MO, IL, IN, OH, WV, VA, MD |
I-80 | ~2,899 | East–West | San Francisco, CA → Teaneck, NJ | CA, NV, UT, WY, NE, IA, IL, IN, OH, PA, NJ |
US Route 60 | ~2,670 | East–West | Quartzsite, AZ → Virginia Beach, VA | AZ, NM, TX, OK, MO, KY, VA |
US Route 2 | ~2,571 | East–West | Everett, WA → Houlton, ME | WA, ID, MT, ND, MN, WI, MI (+ Canada gap) |
I-40 | ~2,555 | East–West | Barstow, CA → Wilmington, NC | CA, AZ, NM, TX, OK, AR, TN, NC |
I-10 | ~2,460 | East–West | Santa Monica, CA → Jacksonville, FL | CA, AZ, NM, TX, LA, MS, AL, FL |
US Route 12 | ~2,484 | East–West | Aberdeen, WA → Detroit, MI | WA, ID, MT, WY, SD, MN, WI, IL, IN, MI |
Quick Picker
Best for history buffs: US Route 30 (Lincoln Highway), US Route 6
Best for scenery: US Route 20, I-90, US Route 50
Best for classic road trip vibes: I-40 (old Route 66 corridor), I-10
Best for northern route: US Route 2, I-90
Best southern route: I-10, I-40
Planning a road trip? Wayback Tours helps you discover the best stops, hidden gems, and historic landmarks along every mile of these great American highways.
Highway vs. Interstate: What's the Difference, Anyway?
Before we get into the rankings, it helps to understand the difference between a highway and freeway — or more precisely, the difference between a US highway and an interstate.
A highway is simply a main public road connecting cities and towns. It can have traffic lights, intersections, and local businesses along the route. An interstate, on the other hand, is a controlled-access road — no traffic lights, no stop signs, just entrance and exit ramps designed for faster travel.
The interstate highway system was created by the Federal-Aid Highway Act of 1956 under President Dwight Eisenhower, who believed a strong road network was essential for both commerce and national defense. The older US highway system — where you'll find roads like US Route 20 and US Route 6 — predates the interstates by decades, going back to 1926.
So when people ask what the longest highway in the US is, the answer depends on what you mean. US Route 20 is the longest if you include all highways. I-90 is the longest if you're talking strictly interstates. We've included both here, because they're all part of the same incredible story.
Fun Fact:
The Dwight D. Eisenhower National System of Interstate and Defense Highways is said to have been inspired in part by the German Autobahn, which Eisenhower encountered during World War II. The idea was to build a network that could move troops and equipment quickly across the country.
Why the Length of a Road Actually Matters
You might wonder why anyone would care how long a highway is. Fair question. But length tells a story.
The longer a road, the more states it crosses, the more communities it connects, and the more history it carries. Many of America's longest highways trace routes that people have been traveling for centuries — old wagon trails, pioneer paths, and railroad corridors that eventually got paved over and widened.
Today, the US interstate highway system spans tens of thousands of miles and moves a huge portion of the country's freight and passenger traffic. But it's the older US highways — the ones that run through small towns and past actual local diners — that often have the most to offer for road trippers who want something more than just getting there fast.
The 11 Longest Highways in the US, Ranked
From Pacific shorelines to New England harbors, these roads cover more ground than most people will drive in a lifetime. Here's a look at each one — what makes it worth your time and what to know before you go.
1. US Route 20 — The Longest Road in the US (~3,365 Miles)
Most people have never driven US Route 20 end to end, but it quietly holds the record for the longest road in the US. It runs from Newport, Oregon on the Pacific coast all the way to Boston, Massachusetts — through mountains, prairies, and small towns most road trippers never see.
What makes this stop different: US 20 is the longest highway in the country, yet it flies completely under the radar. It passes through Yellowstone country in Wyoming, cuts across the rolling hills of Iowa, and winds through upstate New York before hitting the New England coast. If you want to drive across America without touching an interstate, this is your road.
What you need to know before you go:
Route: Newport, OR → Boston, MA
States crossed: Oregon, Idaho, Montana, Wyoming, Iowa, Illinois, Indiana, Ohio, New York, Massachusetts (and more)
Type: US Highway (not an interstate)
Scenic highlights: Yellowstone region, Finger Lakes NY, historic New England towns
Worth it or skip it? Worth every mile if you're after a true slow-road experience — this is America at its most unfiltered.
⭐ What is a Bucket List? Save places you want to visit and come back to later. Your Wayback Tours bucket list keeps track of stops you don't want to forget — perfect for planning future trips.
2. US Route 6 — The Grand Army of the Republic Highway (~3,207 Miles)
US Route 6 has a name that sounds like it belongs on a monument, and in a way it does. Named the Grand Army of the Republic Highway to honor Civil War veterans, this road stretches from Bishop, California — near the edge of the Great Basin Desert — all the way to the tip of Cape Cod in Provincetown, Massachusetts.
The quick pitch: This is one of the lesser-known but historically rich long-distance highways in the country. It once rivaled Route 66 in prominence, and stretches of it still carry that old-highway energy through the American heartland. The longest road in the us conversation often skips US 6, but it absolutely belongs on this list.
What you need to know before you go:
Route: Bishop, CA → Provincetown, MA
States crossed: CA, NV, UT, CO, NE, IA, IL, IN, OH, PA, NY, CT, RI, MA
Type: US Highway
Passes near: Arches National Park UT; Cape Cod National Seashore MA
Worth it or skip it? Worth it for history lovers and anyone who enjoys the character of old US highways over modern interstates.
3. Interstate 90 (I-90) — Longest Interstate in the US (~3,100 Miles)
If you've ever debated which is the longest interstate in the us, the answer is Interstate 90. It runs from Seattle, Washington to Boston, Massachusetts, crossing 13 states through some of the most dramatic scenery the northern US has to offer.
Don't skip this if you like: big views, open road, and iconic American landscapes. I-90 passes through the Cascade Range, the Continental Divide in Montana, the Dakota Badlands, and the Great Lakes region before hitting the Northeast corridor. It also runs through Chicago — one of the busiest stretches of any highway in the country.
What you need to know before you go:
Route: Seattle, WA → Boston, MA
States crossed: WA, ID, MT, WY, SD, MN, WI, IL, IN, OH, PA, NY, MA
Type: Interstate (fully controlled access)
Note: Portions use toll roads (Indiana, Ohio, New York, Massachusetts)
Snoqualmie Pass elevation: ~3,022 feet in Washington
Worth it or skip it? Absolutely worth it — this is arguably the most scenic transcontinental interstate route in the country.
Fun Fact:
Montana has the longest single-state stretch of I-90, covering roughly 550 miles across the state — and in some rural sections, daily traffic counts are said to be among the lowest on the entire interstate.
Wayback Tours makes it easy to save stops along I-90 and every other long highway on this list — build your personalized road trip bucket list and never lose track of a great detour.
4. US Route 30 — The Lincoln Highway (~3,073 Miles)
US Route 30 has a legendary past. Large portions of it trace the historic Lincoln Highway — widely considered the first road to cross the entire United States from coast to coast. It runs from Astoria, Oregon to Atlantic City, New Jersey, cutting through some of the most classically American landscapes you can find.
Why this one stands out: The Lincoln Highway heritage gives US Route 30 a historical weight that most interstates simply don't have. You're driving roads that early 20th-century travelers navigated in cars that were practically built by hand, through towns that have barely changed since then. This is where American road trip culture was born.
What you need to know before you go:
Route: Astoria, OR → Atlantic City, NJ
States crossed: OR, ID, WY, NE, IA, IL, IN, OH, PA, NJ
Type: US Highway
Historical note: Follows the path of the first transcontinental road in America
Worth it or skip it? Worth it if American history and old highway nostalgia are your thing — especially the stretch through small-town Pennsylvania.
5. US Route 50 — The Loneliest Road in America (~3,011 Miles)
Life Magazine once dubbed the Nevada stretch of US Route 50 "The Loneliest Road in America" — and they weren't wrong. For hundreds of miles through the Great Basin Desert, you can drive without seeing much of anything except sky, sand, and the road disappearing into the horizon.
The quick pitch: If solitude and vast emptiness appeal to you, this road delivers. US Route 50 runs from Ocean City, Maryland to West Sacramento, California, passing through the Appalachians, the Great Plains, and the Sierra Nevada along the way. It's a transcontinental journey that rewards patient travelers.
What you need to know before you go:
Route: Ocean City, MD → Sacramento, CA
States crossed: MD, WV, VA, KY, MO, KS, CO, UT, NV, CA
Type: US Highway
Famous stretch: Nevada segment through the Great Basin — long, remote, unforgettable
Worth it or skip it? Worth it for adventurous solo travelers or anyone who wants to experience the kind of open emptiness that's hard to find anywhere else.
6. Interstate 80 (I-80) — Second Longest Interstate (~2,899 Miles)
You want to talk about I-90's closest rival? That's I-80. It runs from San Francisco, California to Teaneck, New Jersey, following a route that closely mirrors the old Lincoln Highway through the heart of the country. It's the main artery for long-haul trucking across the middle of the US.
Don't skip this if you like: big-city bookends with wide-open country in between. I-80 connects San Francisco and the New York metro while rolling through Salt Lake City, Omaha, Des Moines, and the vast emptiness of Wyoming. The Bonneville Salt Flats in Utah alone are worth the detour.
What you need to know before you go:
Route: San Francisco, CA → Teaneck, NJ
States crossed: CA, NV, UT, WY, NE, IA, IL, IN, OH, PA, NJ
Type: Interstate
Notable stops: Bonneville Salt Flats UT; Cuyahoga Valley National Park OH
Worth it or skip it? Absolutely worth it — one of the most practical and varied cross-country routes for first-time transcontinental road trippers.
7. US Route 60 — The Cross-Country Southern Option (~2,670 Miles)
US Route 60 doesn't get the same attention as some of its more famous cousins, but it earns its place on this list by crossing from Quartzsite, Arizona all the way to Virginia Beach, Virginia — through the desert Southwest, the Texas Panhandle, the Ozarks, and Appalachia.
Why this one stands out: This road passes through some genuinely underrated parts of America. The stretch across eastern Oklahoma and the Missouri Ozarks feels like another era entirely, and the Virginia end takes you to the Atlantic coast in a way that most north-south interstates skip entirely.
What you need to know before you go:
Route: Quartzsite, AZ → Virginia Beach, VA
States crossed: AZ, NM, TX, OK, MO, KY, WV, VA
Type: US Highway
Best segments: Arizona desert and the Missouri Ozarks
Worth it or skip it? Worth it for travelers looking for a southern cross-country option that avoids the heavily trafficked I-40 corridor.
8. US Route 2 — The Northern Tier Highway (~2,571 Miles)
If you want to see the wild northern edge of the continental US, US Route 2 is your road. It runs from Everett, Washington to Houlton, Maine — and technically dips into Canada for a stretch before re-entering the US in New York.
The quick pitch: US Route 2 is one of the most scenic and least-traveled long-distance highways in the country. It passes through Glacier National Park, cuts across the wide-open North Dakota prairies, weaves through Minnesota's lake country, and eventually touches the edge of New England. If you want wilderness, this is your shortcut to it.
What you need to know before you go:
Route: Everett, WA → Houlton, ME
States crossed: WA, ID, MT, ND, MN, WI, MI, NY, VT, NH, ME (with a Canada segment)
Type: US Highway
Don't miss: Glacier National Park MT; the Lake Michigan shoreline segment
Worth it or skip it? Worth it if you love wide-open spaces and don't mind a longer drive between towns — this road rewards the patient.
Fun Fact:
US Route 2 is said to be the northernmost east-west highway in the contiguous United States, running closer to the Canadian border than any other comparable route — and it crosses the Continental Divide in Montana at elevations that make the scenery genuinely unforgettable.
9. Interstate 40 (I-40) — The Route 66 Successor (~2,555 Miles)
If you've ever felt the pull of Route 66 but wanted something a bit more drivable, Interstate 40 is your answer. It replaced and runs roughly parallel to the original Mother Road for much of its route, stretching from Barstow, California to Wilmington, North Carolina.
Don't skip this if you like: the American Southwest and a sense of nostalgia for classic road trip culture. I-40 takes you through the Grand Canyon region, across the Texas Panhandle, through the Ozarks, and over the Great Smoky Mountains. If you're pairing this with a southern swing, the best roadside attractions along I-10 make a natural extension of the journey.
What you need to know before you go:
Route: Barstow, CA → Wilmington, NC
States crossed: CA, AZ, NM, TX, OK, AR, TN, NC
Type: Interstate
Tennessee has the longest single-state I-40 stretch at roughly 455 miles
Worth it or skip it? Worth every mile — especially the stretch through New Mexico and Arizona, which offers some of the best scenery on any US interstate.
10. Interstate 10 (I-10) — The Southernmost Transcontinental (~2,460 Miles)
Interstate 10 is the southernmost coast-to-coast interstate in the US, running from Santa Monica, California to Jacksonville, Florida. It's one of the most varied roads in the country — from the Pacific Coast to the Sonoran Desert to the Gulf Coast bayous to the Florida panhandle. We've covered this route in depth in our ultimate I-10 road trip guide.
Why this one stands out: I-10 is the only interstate that lets you start with your feet in the Pacific and end with your feet in the Atlantic. The Texas stretch alone is enormous — longer than some entire states. For overnight planning, our best overnight stops on I-10 guide covers the standout rest stops along the way, and if Texas is your focus, the hidden history and roadside stops along I-10 in Texas is a great read before you head out.
What you need to know before you go:
Route: Santa Monica, CA → Jacksonville, FL
States crossed: CA, AZ, NM, TX, LA, MS, AL, FL
Type: Interstate
Also serves as a hurricane evacuation route for Gulf Coast communities
Worth it or skip it? Worth it — especially for first-time cross-country road trippers who want sunshine, variety, and iconic American cities the whole way through.
11. US Route 12 — The Northern Trail (~2,484 Miles)
US Route 12 runs from Aberdeen, Washington to Detroit, Michigan — a genuinely beautiful and underappreciated road that passes through Nez Perce country in Idaho, the Montana Rockies, the Standing Rock Indian Reservation in the Dakotas, and the Great Lakes shoreline.
Don't skip this if you like: Native American history, mountain scenery, and roads that feel earned. US Route 12 was part of the historic Yellowstone Trail — one of the first attempts at a cross-country highway before the interstate highway system existed. Sections of it are still rugged, slow, and deeply rewarding. If you're building out a northern road trip that also dips south, the best stops on I-75 from Michigan to Florida pairs naturally with this route's eastern end.
What you need to know before you go:
Route: Aberdeen, WA → Detroit, MI
States crossed: WA, ID, MT, WY, ND, SD, MN, WI, IL, IN, MI
Type: US Highway
Crosses the Continental Divide at MacDonald Pass (~6,312 ft) in Montana
Worth it or skip it? Worth it for the adventurous traveler who wants something off the beaten interstate path — and isn't in a hurry.
Bonus: What Is the Longest Overwater Highway in the US?
If you're wondering about the longest over-water highway in the US, that title goes to the Lake Pontchartrain Causeway in Louisiana.
The causeway stretches just under 24 miles across Lake Pontchartrain, connecting Metairie (near New Orleans) to Mandeville on the north shore. It holds the Guinness World Record for the longest bridges in the us over water on a continuous span — and at its midpoint, you literally cannot see land in any direction.
While the causeway isn't technically part of the numbered US highway system, it's an essential part of the Greater New Orleans regional road network. It was first completed in 1956 — the same year the highway act that created the interstate system was signed. A second parallel span was added in 1969.
If you're driving through Louisiana on I-10, the causeway is a worthy detour. For more on what to see along that stretch of the south, check out the best overnight stops on I-95 and best places to stop on I-95 on the way to Florida if your route continues up the East Coast after Florida.
And if crossing nearly 24 miles of open water in a car sounds a little unnerving — it is, in the best possible way.
Fun Fact:
The Lake Pontchartrain Causeway is said to be so long that drivers lose sight of land for a stretch of roughly 8 miles in the middle. It even has its own Causeway Police force that patrols the bridge around the clock.
How Does the US Compare to the Longest Highway in the World?
The longest highway in the world is generally considered to be the Pan-American Highway — a network of roads running from Prudhoe Bay in Alaska all the way down to the tip of South America. Depending on how you measure it, the total route spans tens of thousands of miles.
Within a single country, Australia's Highway 1 is often cited among the world's longest national highways, circling the entire continent. Russia also has several extremely long roads given its sheer size.
But the US holds its own. With I-90 alone covering more than 3,000 miles — and US Route 20 stretching nearly 3,400 — America's road network is among the most extensive and road-trip-friendly on earth. And unlike many of the world's longest roads, US highways actually pass through places worth stopping.
Ready to start planning your road trip? Head to Wayback Tours to start saving your favorite stops and building your ultimate American highway bucket list — all in one place.
Conclusion
America's roads are more than just ways to get from point A to point B. The longest highways in the US tell the story of a country built on movement — from the Lincoln Highway's first coast-to-coast route to the Eisenhower interstate system that followed.
Whether you're planning a full transcontinental adventure or just curious about how these roads connect the country, every one of these highways has something remarkable waiting along its route. You just have to get out there.
Save these stops, build your own road trip bucket list, and keep track of every place you want to visit — all in one place with Wayback Tours.
FAQs
Is I-90 the same as the Massachusetts Turnpike?
In Massachusetts, yes — I-90 runs concurrently with the Massachusetts Turnpike (MassPike) for its entire in-state stretch. So if you've driven the Pike between Boston and the New York state line, you've been on America's longest interstate.
What is the longest north-south highway in the US?
Among interstates, I-75 and I-95 are among the longest north-south routes. I-75 runs from Sault Ste. Marie, Michigan down to Miami, Florida, while I-95 hugs the East Coast from Maine all the way to Miami — two of the most driven corridors in the country for anyone heading toward Florida.
What is the longest straight highway in the US?
US Route 20 through parts of North Dakota and Wyoming has some impressively long straight stretches, but the most commonly cited example is US Route 83 in North Dakota — sometimes called the "Highway to Nowhere" for its long, uninterrupted runs across the Great Plains.
Are there any notable highway tunnels worth knowing about?
The Anton Anderson Memorial Tunnel in Alaska is generally considered among the longest highway tunnels in the US at roughly 2.5 miles. For the lower 48, the longest highway tunnel in the us conversation often points to the E. Johnson Memorial Tunnel on I-70 in Colorado — one of the highest and most notable tunnels in the country.
What's the difference between a US Route and an interstate?
A US Route is part of the original United States Numbered Highway System established in 1926. These roads pass through towns, can have traffic lights, and vary widely in character. The interstate vs highway distinction comes down to access — interstates are controlled-access roads with on and off ramps, no traffic lights, and generally higher speed limits, built starting in 1956 under the Eisenhower highway system.
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