Interstate 90 (I-90) is the longest interstate in the United States. It goes from Boston in the east to Seattle in the west, and it starts in the east in Boston.
The eastern end of I-90 is less than half a mile from Boston Harbor, and the western end is about the same distance from Elliott Bay. This means that both the Atlantic and Pacific Oceans are less than a mile away from I-90.
It really is a highway from coast to coast.
How long is Interstate 90?
The whole length of Interstate 90 is 3,021 miles (or 4,862 km).
What states does Interstate 90 go through?
I-90 goes through 13 different states.
These are the states:
New York City
The state of South Dakota
How long is I-90 in MA?
How long is I-90 in NY?
How long is I-90 in PA?
How long is I-90 in OH?
How long is I-90 in IN?
How long is I-90 in IL?
How long is I-90 in WI?
How long is I-90 in MN?
How long is I-90 in SD?
How long is I-90 in WY?
How long is I-90 in MT?
How long is I-90 in ID?
How long is I-90 in WA?
Which cities does Interstate 90 go through?
Along with Seattle and Boston, where it starts and ends, Interstate 90 goes through or near a number of large cities. For the purposes of this article, we’ll call a city “large” if it has 100,000 or more people living there.
These are their names:
Syracuse, New York
South Bend, Indiana
Sioux Falls, SD
I-90 also goes through a number of smaller cities, such as:
Rapid City, South Dakota
Coeur d’Alene, ID
Other Notable Places Along Interstate 90
Along with the cities it goes through, I-90 goes by a number of interesting towns or attractions.
These things are:
State Forest of October Mountain (Appalachian Trail Head)
Lake Erie (rolls right over it in Cleveland)
The University of Notre Dame
National Park of Badlands
National Forest of the Black Hills
Sturgis, SD (known for its motorcycle rally)
Bighorn Forest National Park
The National Forest of Mt. Baker-Snoqualmie
How long did it take to build I-90?
It took 31 years to build most of Interstate 90. It was first ordered in 1956, and by 1987, it had gone all the way across the country.
But in 1993, it went farther to Seattle, and in 2003, it went farther to Boston.
So, I-90 was built between 1956 and 2003, which means it took 47 years to finish!
How long does it take to drive I-90?
When speed limits are taken into account, it takes about 45 hours to drive from one end of I-90 to the other, or almost two days if you drive straight through. (Let’s assume you have a very nice car and a second driver.)
But that doesn’t take into account traffic, gas stops, or any other stops you’ll want to make along the way (there will be a lot).
So, if you only drive for eight hours a day, which is much more reasonable, you’ll have nearly six days of good road trip time along the U.S.’s northernmost cross-country interstate.
See What Is The Longest Highway In The U.S.? for information about the longest highway in the country.