Interstate 90 is the longest interstate highway in the United States. It begins in Seattle, Washington at S. Edgar Martinez Dr. and 4th Avenue S. next to Safeco Field and ends in Boston, Massachusetts at Logan International Airport.

Contents

1 Length 2 Major Cities Along the Route 3 Intersections with other Interstates 4 Spur Routes 5 Unusual Hazards 6 Notes

Length

Miles	km	state
297.52	478.81	Washington
73	120	Idaho
558	898	Montana
207	333	Wyoming
412	663	South Dakota
275	443	Minnesota
188	303	Wisconsin
103	166	Illinois
157	253	Indiana
244	393	Ohio
47	76	Pennsylvania
391	629	New York
160.3	258	Massachusetts
3,112.82	5,009.60	Total

Major Cities Along the Route

• Seattle, Washington
• Spokane, Washington
• Missoula, Montana
• Billings, Montana
• Rapid City, South Dakota
• Sioux Falls, South Dakota
• Rochester, Minnesota (Home of the Mayo Clinic)
• Madison, Wisconsin
• Rockford, Illinois
• Chicago, Illinois
• Gary, Indiana
• South Bend, Indiana
• Toledo, Ohio
• Cleveland, Ohio
• Erie, Pennsylvania
• Buffalo, New York
• Rochester, New York
• Syracuse, New York
• Albany, New York
• Springfield, Massachusetts
• Worcester, Massachusetts
• Boston, Massachusetts

Intersections with other Interstates

• Interstate 5 in Seattle, Washington
• Interstate 405 in Bellevue, Washington
• Interstate 82 in Ellensburg, Washington
• Interstate 15 in Butte, Montana. They stay merged for about 9 miles (14.5 km).
• Interstate 94 in Billings, Montana
• Interstate 25 in Buffalo, Wyoming
• Interstate 29 in Sioux Falls, South Dakota
• Interstate 35 in Albert Lea, Minnesota
• Interstate 94 in Tomah, Wisconsin. They stay joined until Madison, Wisconsin.
• Interstate 39 in Portage, Wisconsin. They stay joined until Rockford, Illinois.
• Interstate 43 in Beloit, Wisconsin
• Interstate 94 in Chicago, Illinois. They stay joined for a few miles.
• Interstate 55 in Chicago, Illinois
• Interstate 65 in Gary, Indiana
• Interstate 94 in Portage, Indiana
• Interstate 80 in Portage, Indiana. They stay merged until Clearview, Ohio.
• Interstate 69 in Fremont, Indiana
• Interstate 75 in Toledo, Ohio
• Interstate 71 in Cleveland, Ohio
• Interstate 77 in Cleveland, Ohio
• Interstate 79 in Erie, Pennsylvania
• The eastern Interstate 86 in Erie, Pennsylvania
• Interstate 81 in Syracuse, New York
• The eastern Interstate 88 in Schenectady, New York
• Interstate 87 in Albany, New York
• Interstate 91 in Springfield, Massachusetts
• Interstate 84 in Sturbridge, Massachusetts
• Interstate 95 in Newton, Massachusetts
• Interstate 93 in Boston, Massachusetts

Spur Routes

• Rapid City, South Dakota - I-190
• Chicago, Illinois - I-190 (provides a direct route to O'Hare International Airport), I-290
• Cleveland, Ohio - I-490
• Buffalo, New York - I-190, I-290, I-990
• Rochester, New York - I-490, I-590
• Spur to Corning, New York - I-390
• Syracuse, New York - I-690
• Utica, New York - I-790
• Schenectady, New York - I-890
• Spur to Marlborough, Massachusetts - I-290
• Spur to Leominster, Massachusetts - I-190 (This is actually a spur from I-290 in Worcester, Massachusetts)

Unusual Hazards

One of the most peculiar and hazardous stretches of Interstate 90 is the section of highway passing through downtown Cleveland, Ohio, known locally as "Dead Man's Curve". Here, the road takes a nearly 90-degree turn. While there are plenty of large signs and flashing lights alerting motorists to this turn, there have still been a large number of accidents due to inattentive motorists.

Notes

In 2003, the Seattle terminus was re-engineered to better accommodate traffic from the two nearby sports stadiums. I-90 westbound still ends at its previous location next to Qwest Field, but eastbound begins about 1/4 mile (.4 km) south at Edgar Martinez Dr. near the roof shed of Safeco Field at an interchange with 4th Avenue S.

Almost all of the New York portion of the road is a toll road, the major east-west portion of the New York State Thruway, operated by the New York State Thruway Authority. It was originally constructed as part of the Thruway project in the middle 1950s and received its current designation as Interstate 90 in 1958. The Massachusetts stretch, also a toll road built in the mid-1950s, is known as the Massachusetts Turnpike.

I-90 incorporates two of the longest floating bridges in the world, the Lacey V. Murrow Memorial Bridge and the Homer M. Hadley Memorial Bridge, which cross Lake Washington from Seattle to Mercer Island, Washington. They are the second and fifth longest such bridges, respectively.

I-90 terminated at Interstate 93 in Boston until it was connected through to the Ted Williams Tunnel in January 2003 as part of the Big Dig, extending I-90 to Boston's Logan International Airport, an additional 1.3 miles (2 km) beyond the 3,111.52 miles (5,007.51 km) already paved.

Until 1995 in Montana right by the Idaho border, I-90 was not a divided highway for a few stretches. Until 1999, the speed limit in Montana was "reasonable and prudent"; it is now 75 mph (121 km/h).

Not only is the I-90 section of the NYS Thruway marked backwards, with mile numbers going down as you go east, but there were two metric only signs going westbound. They were around Syracuse, which is about 100 miles (161 km) from Canada. The NYS Thruway administration decided to test metric signage, which may have included [briefly] an 88 km/h speed limit sign, on the Thruway. There is a rumor that a state representative opposed one of the metric pushes. The Thruway chose his district (Liverpool, next to the former GE plant) as the test site. There was also a sign displaying the distance to the Interstate 81 interchange in kilometers in Dewitt.

I-990 is the highest number given to an Interstate.

To add to the quirks about the longest interstate, it also has the longest distance twinned with another interstate (I-80 in Ohio and Indiana, I-94 in Illinois and Wisconsin) in the most states 4 (Ohio, Indiana, Illinois, and Wisconsin.) It also intersects the same interstate six times (I-94 near Michigan City IN, Chicago (southside), Chicago (northside), Madison WI, Tomah WI, and Billings MT).

It has been said that technically I-90 is not a complete "Interstate" as the Chicago Skyway did not meet the current interstate standards, making I-80 the longest "true/no interrupted" interstate without any gaps between the endpoints.

Between LaPorte, Indiana and Toledo, Ohio, with Interstate 80, it is nowhere more than 10 miles (16 km) from the Michigan state line.

Primary Interstate Highways	Missing image Interstate_blank.png Interstate Highway marker
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