Discover the 12 Longest Roads in the United States

Ready for a road trip? And we do mean trip, because we’re about to travel the longest roads in the United States, crisscrossing the continent from coast to coast and north to south. So fasten your seatbelt, crank down the window for some fresh air, and let’s hit the roads!

The U.S. Federal Highway System

Broadly speaking, the network of roads that connects the states and cities of the United States had three major growth spurts. Before the first automobiles, bicyclists were campaigning for the federal government to invest in better roadways. When cars came along, this Good Roads Movement grew stronger. Soon a network of informal “auto trails” sprang up, maintained to a greater or lesser degree by civic or private groups. As state governments got more involved in creating and maintaining roads, the United States Numbered Highway System was instituted in 1926 to organize ad-hoc trail designations consistently. That’s when those familiar black-and-white shield “U.S. Route” signs were introduced. Routes running north to south were given odd numbers, and routes running east to west were given even numbers.

Decades later, the Eisenhower administration passed the Federal-Aid Highway Act of 1956, authorizing the creation of a 41,000-mile interstate highway system. (It’s currently reached about 46,000 miles in total length.) The new roadways would be designed for high-speed driving, to allow speedy, safe travel across the country. They were also touted as an efficient way to evacuate cities in the case of atomic attacks. As with the old numbered highway system, interstate highways are designated with odd numbers for north-south routes and even numbers for east-west routes.

The longest roads in the United States include both interstate highways and older U.S. routes.

#1 U.S. Route 20, the longest road in America

Length: 3,365 miles

Stretching from Boston, Massachusetts to Newport, Oregon, the longest road in the United States was only the second-longest for quite a stretch of time. Its original proposed length was shortened, ending at Yellowstone National Park, with Route 30 picking up the course through to Oregon. Later an extension was added, bringing the highway to 3,277 miles. However, this was still short of Route 6, which stretched 3,652 miles from Provincetown, Massachusetts to Long Beach, California. But in 1965, Route 6 was shortened on the California end, bringing Route 20 to the top spot.

#2 US-6

Length: 3,277 miles

As mentioned, this was once the longest road in America. But even in the # 2 spot, it’s pretty dang long. It began as a 700-or-so-mile road connecting Massachusetts to Pennsylvania; in 1931 Route 6 was extended to Colorado. In 1937 U.S. 6 became a transcontinental highway, reaching California at a length of 3,652 miles. Route 6 is also known as the “Grand Army of the Republic Highway,” in honor of the Union soldiers of the Civil War. This designation was adopted separately by the individual states the route passes through, and a formal dedication was held in 1953.

#3 U.S. Route 30

Length: 3,073 miles

America’s third-longest highway connects Atlantic City, New Jersey with Astoria, Oregon. This makes it one of the main east-west routes in the numbered highway system, and in fact, it’s the only route that’s been coast-to-coast since the numbered route system began. Most of U.S. 30 corresponds to the so-called Lincoln Highway, a coast-to-coast route from the auto trial days. Named after the president and organized by the eponymous Lincoln Highway Association, the highway lost its name when the highway numbers were instituted, with the stretch from Philadelphia, Pennsylvania to Granger, Oregon now designated as U.S. 30.

#4 Interstate 90

Length: 3,022 miles

Though not the longest road, I-90 is the longest interstate road in the U.S. Highway System. Its western end originates in Seattle, Washington, and it passes through 13 states before finishing in Boston, Massachusetts. It also has the distinction of being the interstage highway with the most toll mileage, 25% of its total route.

#5 U.S. Route 50

Length: 3,007 miles

This route, from Ocean City, Maryland to Sacramento, California isn’t the only road to connect America’s east and west coasts. But the course it follows has earned U.S. 50 the unique nickname of “The Loneliest Road in America.” The route passes through few cities or towns, and the portion in western Nevada is one of the nation’s least-traveled highways. That’s not necessarily bad, though. Travelers can expect breathtaking views of scenery and wilderness, a visual sampler of almost every kind of landscape in the U.S.

#6 Interstate 80

Length: 2,900 miles

Connecting Teaneck, New Jersey to San Francisco, California, I-80 almost made it all the way to the Pacific Ocean. But community opposition prevented the planned Ocean Beach construction.

#7 U.S. Route 2

Length: 2,643

The name of this route, which reaches from Everett, Washington to Houlton, Maine, is something of an anomaly. According to the numbered highway system, major east-west routes get two-digit numbers that are multiples of ten. And they’re assigned in descending order from north to south. But that scheme meant the northernmost route had to be numbered Route 0, a designation the planners weren’t too crazy about. Since all east-west routes had to be given even numbers, it was decided that Route 2 would be the name of this road.

#8 Interstate 40

Length: 2,557 miles

A major route connecting the southeastern and southwestern portions of the U.S., I-40 crosses 8 states as it winds from Barstow, California to Wilmington, North Carolina. Along the way it passes through the Mojave Desert, crosses the Colorado River, the Texas panhandle, the Mississippi River, and the Great Smoky Mountains. And it passes through or near the cities of Albuquerque, Amarillo, Little Rock, Memphis, Jackson, Nashville, Durham, and Raleigh. Pretty good!

#9 U.S. Route 1

Length: 2,321 miles

This road owes its #1 designation to its location as the easternmost of the north-south routes under the numbered highway system. But we can also consider the so-called “Atlantic Coast Highway” to be the first highway in American history. U.S. 1 follows the shoreline of the North American continent from Fort Kent, Maine, to Miami Florida. Its geography made its earliest segments the most important roads in the American colonies. Sections of this route have been in use for 300 years. George Washington traveled it; Revolutionary War battles occurred near it. Today U.S. 1 is a principal tourist route, and the stretch from New York City to Philadelphia carries heavier average traffic than any other road of equal length in the world.

#10 Interstate 10

Length: 2,460 miles

The southernmost of the interstate system’s east-west routes, I-10 reaches from Santa Monica, California to Jacksonville, Florida. Texas takes up a full third of its length since it crosses the Lone Star State at its widest point. That’s the longest stretch of any interstate highway to be found in any single state.

#11 U.S. Route 64

Length: 2,326 miles

U.S. 64 runs from Teec Nos Pos, Arizona to Whalebone Junction, North Carolina, passing through six southern states (and coming close to, but not quite touching Texas). Its scenic stretches include part of the Trails of the Ancients in New Mexico and the Ocoee Scenic Byway in Tennessee.

#12 Interstate 70

Length 2,151

Connecting Baltimore, Maryland, and Cove Fort, Utah, I-70 includes some breathtaking views in Colorado, including Glenwood Canyon and Vail Pass. But early planning did not include an east-west interstate route crossing the Centennial State. Thanks to vociferous protests and politicking, the Federal-Aid Highway Act of 1956 included a route through Colorado into Utah.

Summary of the 12 Longest Roads in the United States

The photo featured at the top of this post is © Trong Nguyen/Shutterstock.com