President Dwight D. Eisenhower considered the U.S. Interstate System one of his most important achievements in office, and Americans agree, having dubbed the highway network the “Greatest Public Works Project in History,” the Federal Highway Administration says.
At a total of 46,876 miles long, the interstate network is estimated to have cost $128.9 billion to construct, with the federal government contributing 90% of that cost. The highway network has succeeded in making road travel safer and more efficient. The Interstate System is the safest road system in the country, with a fatality rate of 0.8 compared with a rate of 1.46 for all roads. When the construction of the interstates began in 1956, the fatality rate was 6.05, the Federal Highway Administration reports.
Today, the interstates are essential to American travel—as of 2016, approximately a quarter of all vehicle miles driven in the U.S. took place on the Interstate System, according to national data.
Stacker has compiled a list of the longest interstates in the United States using data from the Federal Highway Administration. Read on to find out which ones are the lengthiest.
Total length: 528 miles
I-49 runs through Louisiana, Arkansas, and Missouri, and passes through several major southern cities, including Kansas City, Shreveport, and Fayetteville. In 2017, a new 4.25-mile segment of the interstate was added in Louisiana, according to KSLA 12 News.
Total length: 610.1 miles
Five states are home to I-77: North Carolina, South Carolina, Virginia, West Virginia, and Ohio. The interstate is home to the East River Mountain Tunnel, which connects Virginia and West Virginia, and is one of only two places in the U.S. where a mountain road tunnel crosses a state line, Appalachian Magazine has reported.
Total length: 622.1 miles
I-76 passes through Colorado, Nebraska, Ohio, Pennsylvania, and New Jersey, and is a gateway to both Denver and Philadelphia. It has been thought that the interstate was numbered to honor Philadelphia as the city where the Declaration of Independence was signed in 1776, but the Federal Highway Administration has debunked that theory.
Total length: 636.7 miles
Texas, Oklahoma, and Missouri are all home to I-44, which runs through Oklahoma City and Springfield. Though even-numbered interstates run east to west, according to the Federal Highway Administration, I-44 runs southwest to northeast.
Total length: 666.1 miles
I-85 traverses Alabama, Georgia, South Carolina, North Carolina, and Virginia, and passes through Montgomery, Atlanta, and Charlotte. When the highway was opened in 1964, it became South Carolina’s first Interstate Highway, the Federal Highway Administration has said.
Total length: 700.8 miles
Six states—Indiana, Michigan, Kentucky, Mississippi, Tennessee, and Texas—rely on I-69, which runs through Indianapolis, Flint, Memphis, Houston, and Corpus Christi. The interstate is one of the country’s “Corridors of the Future” as designated by the Transportation Department, and was chosen based on its proposal to limit traffic congestion.
Total length: 755.5 miles
I-29 passes through Missouri, Iowa, North Dakota, and South Dakota, stopping in Fargo, Kansas City, and Sioux City, and racking up more than 700 miles. The interstate crosses into Canada at the Pembina-Emerson border crossing. This is the only border crossing open 24 hours a day in North Dakota, making it the most heavily trafficked, according to the Mid-America Freight Coalition.
Total length: 855.0 miles
Tennessee, Virginia, West Virginia, Maryland, Pennsylvania, and New York are all linked by I-81, which runs through several cities including Binghamton, Syracuse, Harrisburg, Scranton, and Hagerstown. According to Miller’s House Museum in Virginia, the interstate largely follows a path down the Appalachian Mountains created by migrating animals and early American settlers.
Total length: 887.3 miles
I-65 traverses Alabama, Kentucky, Tennessee, and Indiana, connecting cities such as Birmingham, Montgomery, Louisville, and Indianapolis. In 2017, a Kentucky woman gave birth to a healthy baby boy on I-65 North in the backseat of her car, WLTX 19 reported.
Total length: 963.5 miles
Missouri, Illinois, Indiana, Kentucky, West Virginia, and Virginia are all connected by I-64, which passes through St. Louis, Louisville, Charlottesville, Richmond and Virginia Beach. In 2009, Missouri dedicated the section of I-64 that runs through St. Louis as Jack Buck Memorial Highway, in honor of the city’s famed Cardinals sportscaster, according to Major League Baseball.
Total length: 964.3 miles
I-55 links Louisiana, Mississippi, Tennessee, Arkansas, Missouri, and Illinois, and runs through Jackson, Memphis, Springfield, and Chicago. At most points, the interstate travels parallel to the Mississippi River. The route is also home to two major airports—the St. Louis Lambert International Airport and the Springfield-Branson National Airport, according to the Mid-America Freight Coalition.
Total length: 1002.3 miles
Oregon, Idaho, Utah, Pennsylvania, New York, Connecticut, and Massachusetts are connected by the cross-country I-84, which stops in Portland, Hartford, Danbury, and Boise City. Both Oregon and Idaho recognize the interstate as the Vietnam Veterans Memorial Highway, according to The Spokesman-Review.
Total length: 1061.7 miles
I-25 runs through just three states: New Mexico, Colorado, and Wyoming. The interstate provides access to Albuquerque, Colorado Springs, Denver, Casper, and Cheyenne. A section of the road in New Mexico closely follows the original path of historic U.S. Route 66, which followed the trail of the Santa Fe Railroad, according to the National Center for Preservation Technology and Training.
Total length: 1381.3 miles
I-5 traverses California, Oregon, and Washington, and runs parallel to the West Coast of the United States from Mexico to Canada. The construction of the interstate in the 1950s and 1960s helped to expand suburbia in Los Angeles and attracted major companies to California, including Disney, Lockheed Martin, Douglas, and Hughes, according to KCET.
Total length: 1433.5 miles
California, Nevada, Arizona, Utah, Idaho, and Montana are all connected throughout I-15, which links San Diego, Las Vegas, Salt Lake City, and Helena. Annually, 25 million people travel the access route between southern California and Las Vegas, and is the primary transportation corridor in Utah, according to the I-15 Mobility Alliance.
Total length: 1539.4 miles
I-20 connects Texas, Louisiana, Mississippi, Alabama, Georgia, and South Carolina, stopping in cities including Dallas, Fort Worth, Jackson, Birmingham, Atlanta, and Columbia. Parts of the interstate in Texas have a speed limit of 80 miles per hour, making it one of the highest speed limits in the country, according to the Texas Department of Transportation.
Total length: 1568.4 miles
Texas, Oklahoma, Kansas, Missouri, Iowa, and Minnesota are all linked by I-35, which stops in Austin, San Antonio, Oklahoma City, Kansas City, Des Moines, and Duluth. This interstate is the only one in the country that has two sets of two parallel branches: I-35E going through Dallas while I-35W goes through Fort Worth, and a similar situation in the Minneapolis and St. Paul area, according to the Federal Highway Administration.
Total length: 1585.2 miles
I-94 crosses Montana, North Dakota, Minnesota, Wisconsin, Illinois, Indiana, and Michigan, and includes the cities of Bismarck, Minneapolis, Milwaukee, Chicago, and Ann Arbor. The interstate is the only east-west highway in the U.S. with a direct connection to Canada, linking from I-90 in Seattle to Toronto via Ontario Highway 401, according to Greater Lansing Area Clean Cities.
Total length: 1786.5 miles
Florida, Georgia, Tennessee, Kentucky, Ohio, and Michigan are all home to I-75, which crosses Tampa, Atlanta, Knoxville, Cincinnati, Detroit, and Flint. A study conducted in the 1970s on an area of I-75 in Cincinnati that was known for car accidents found that most of the crashes happened on Sundays and 85% of the involved drivers were men, according to The Globe and Mail.
Total length: 1919.3 miles
I-95 crosses 16 states, which include Florida, Georgia, North Carolina, South Carolina, Virginia, Washington, D.C., Maryland, Delaware, Pennsylvania, New Jersey, Connecticut, New York, Rhode Island, Massachusetts, New Hampshire, and Maine, making it the interstate that includes the most states. It was also the priciest interstate to build, costing $8 billion, according to the Federal Highway Administration.
Total length: 2150.6 miles
I-70 passes through Utah, Colorado, Kansas, Missouri, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, and Maryland. The eastern terminus of the interstate is a parking lot near the Social Security Administration building in Baltimore, according to the Federal Highway Administration.
Total length: 2460.3 miles
I-10 runs through California, Arizona, New Mexico, Texas, Louisiana, Mississippi, Alabama, and Florida. This interstate stretches from Santa Monica, California, to Jacksonville, Florida, and helped to shape cities like Houston and Phoenix into fast-growing and car-dependent metropolises, according to the National Museum of American History.
Total length: 2556.6 miles
California, New Mexico, Arizona, Texas, Oklahoma, Arkansas, Tennessee, and North Carolina are all home to I-40, which runs from Barstow, California, to Wilmington, North Carolina. Every fall and summer, the North Carolina Department of Transportation plants wildflowers including poppies, sunflowers, daisies, and coneflowers along the route within the state, according to the Wilmington Star News.
Total length: 2899.6 miles
I-80 passes through California, Nevada, Utah, Wyoming, Nebraska, Iowa, Illinois, Indiana, Ohio, Pennsylvania, and New Jersey—a total of 11 states. This interstate is considered to be the “modern reincarnation” of the Lincoln Highway, which was known as America’s first transcontinental road, according to the Federal Highway Administration.
As the longest interstate in the U.S., I-90 connects Washington, Idaho, Montana, Wyoming, South Dakota, Minnesota, Wisconsin, Illinois, Indiana, Ohio, Pennsylvania, New York, and Massachusetts. However, it is not the nation’s longest road—that would be U.S. 20, a 3,365-mile road that extends from Boston to Newport, Oregon, according to the Federal Highway Administration.