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From Boston to Seattle lies the longest highway in the United States. Traversing through 13 northern states, Interstate 90 is privy to dozens of historical locations, curious roadside attractions, and miles of scenic wonders. It’s a 3,000-mile journey from the history-rich Northeast cities through the upper Midwest’s wide-open spaces. It will also take you from the Rockies’ stunning landscapes to the Pacific Northwest coasts.
In other words, it’s quite a ride!
What Is the Longest Highway in the US?
First conceived in 1956 with Federal-Aid Highway Act, Interstate 90 incorporated many existing highways, roads, and trails into one transcontinental freeway. The last completed section to connect the east and west coasts ended in 2003, making this interstate 3,021 miles long.
Many of the replaced roads by I-90 were existing toll roads like the Ohio and Massachusetts Turnpikes, the Indiana Toll Road, and the New York State Thru-Way. By building connecting roads from these, the completed Interstate 90 led its drivers through the Northeast. It also led them through the Great Plains, the Rocky Mountains, and the Pacific Northwest on one long excursion.
Which States Does I-90 Go Through?
Interstate 90 begins (or ends, depending upon your direction) in Massachusetts, traveling west through New York, Pennsylvania, Ohio, Indiana, and Illinois. It also goes through Wisconsin, Minnesota, South Dakota, Wyoming, Montana, Idaho, and ends in Washington. It connects the east coast to the west, starting in historic Boston and ending in Seattle.
The Best Sites to See Along the Longest Highway in the US
Over the course of 3,021 miles, there are hundreds of things to see. So, you can imagine how difficult it was to narrow our “Best Sites” down to 10 on the longest highway in the United States list. See if you can expound upon these on your next trip down I-90:
World’s Smallest Church in New York
Address: Sconondoa Road, Oneida, New York
How Far Off I-90: Located approximately 1.25 miles south of Interstate 90
At 18 square feet, the world’s smallest church in New York can only hold three people at a time. The Cross Island Chapel is also unique in that it can only be accessed by boat or swimming, as it sits in the middle of a pond in upstate New York. Built in 1989, it hosts weddings and the occasional fisherman looking for a confessional!
Olde Avon Village in Ohio
Address: 36840 Detroit Rd, Avon, OH
How Far Off I-90: Located 1.5 miles south of Interstate 90
A new take on a shopping mall along the longest highway in the U.S., Olde Avon Village is a collection of restored buildings and newly constructed stores that offer restaurants, gift shops, and services. From jewelry to flowers and antiques to clothing, the village shops attract locals and tourists. Spa and salon services, home furnishings, and collectibles are also available.
Keep in Mind: Is I-90 one of the most Dangerous Highway in the US? Click the link to learn which highways are and if you’ve driven them!
Witches Gulch in Wisconsin
Address: Wisconsin Dells, Wisconsin 43.6756, -89.8014
How Far Off I-90: Upper Dells boat launch is less than a mile from Interstate 90
Located within the Wisconsin Dells, Witches Gulch is a canyon carved from the sandstone cliffs in the region. Wind and water erosion left a narrow slot canyon filled with ferns, moss, and several whirlpools. It is accessible only by boat tour with the Upper Dells Boat Tour.
Jolly Green Giant Statue in Minnesota
Address: 1130 Giant Drive, Blue Earth, Minnesota
How Far Off I-90: Located half a mile south of Interstate 90
A 55-foot-tall statue of the Jolly Green Giant stands in Blue Earth, Minn., as a reminder that progress tried to bypass the city when I-90 was built. A local radio station owner installed the giant to entice highway drivers to get off the highway and visit the town just south of the new freeway.
Corn Palace in South Dakota
Address: 604 N. Main St., Mitchell, South Dakota
How Far Off I-90: Located approximately 1.5 miles north of Interstate 90
A concrete and brick building that displays unique folk art in the form of corn sits in downtown Mitchell, S.D. When first built in 1892, locals used it to demonstrate the fruitfulness of local farmland. However, today, the Corn Palace acts as a tourist magnet, with rotating themes designed in corn on its exterior.
Mount Rushmore in South Dakota
Address: 13000 SD-244, Keystone, South Dakota
How Far Off I-90: Located 25 miles southwest of Interstate 90
This granite sculpture of four legendary American presidents lies amid the Black Hills. Conceived in 1923 as a way to bring tourists to South Dakota, Mount Rushmore’s completion happened in 1941. It was a monument to the nation’s birth, growth, development, and preservation. Each head in the sculpture is 60 feet tall, and the mountain is 5,725 feet above sea level. It is part of the National Park System (NPS) and listed as a national memorial.
Keep in Mind: Is there a 5th face on Mount Rushmore? Many seem to think so! Let’s take a look and see if there’s a hidden face at Mount Rushmore you may have missed!
Devils Tower National Monument in Wyoming
Address: WY 110, Devils Tower, Wyoming
How Far Off I-90: Located 32 miles northeast of Interstate 90
A huge igneous monolith overlooks the prairies of northeastern Wyoming. Devils Tower was named the first national monument by Theodore Roosevelt in 1906. Today many tourists put it on their travel lists because of its prominence in the movie “Close Encounters of the Third Kind.” The butte has religious importance to several Native American tribes. As such, the monument, along the longest highway in the U.S., is closed during June to rock climbers for tribal rituals.
Little Bighorn Battlefield National Monument in Montana
Address: I-90 Frontage Road, Crow Agency, Montana
How Far Off I-90: Located on the Frontage Road adjoining Interstate 90
The site of Custer’s last stand, Little Bighorn, is a large grassy area overshadowed by a national cemetery that houses the bodies of the soldiers who died here. Red granite markers are also throughout the hillside, marking the burials of Cheyenne and Lakota Indians who fought and died here.
Coeur D’ Alene, Idaho
Address: Couer D’Alene, Idaho
How Far Off I-90: Interstate 90 runs through town
Beginning as a fort town, Couer D’Alene was built on Lake Couer D’Alene and named after the Native American tribe that lived in the area. The city grew with an influx of prospectors, trappers, and miners. They flocked to the area in the 1870s. Today, it’s a town of 50,000 and a destination for outdoor adventurers along the longest highway in the U.S.
Snoqualmie Falls in Washington
Address: WA-202, Snoqualmie, Washington
How Far Off I-90: Located 4 miles northeast of Interstate 90
This dramatic 268-foot-tall waterfall is one of the most photographed in the northwest. Listed on the National Historic Register, Snoqualmie Falls has an observation deck and adjacent gift shop. A short hike from the parking lot will provide the perfect view of this stunning waterfall.
Plan an Epic Trip Along the Longest Highway in the US
For an all-encompassing trip across America, nothing beats a ride on the longest highway in the U.S. Interstate 90 will energize you with its bustling cities and towns, then feed your soul with majestic landscapes as far as the eye can see. Along the way, the road offers a bit of humor and whimsy with quirky roadside attractions. And it will fill you with a sense of appreciation for our immense country as you finish exploring its 3,021-mile ribbon of road.
I-90 is the longest Interstate Highway, but the longest highway in the United States is US 20, which runs from Boston, MA to Newport, OR and is 3365 miles long.