Interstate 90
Route information
Length:	3,101.77 mi[1] (4,991.81 km)
Existed:	1956 – present
Major junctions
West end:	SR 519 or 4th St S in Seattle, WA
	I-5 in Seattle, WA I-15 near Butte, MT I-25 near Buffalo, WY I-35 in Albert Lea, MN I-55 in Chicago, IL I-65 in Gary, IN I-75 near Toledo, OH I-95 in Weston, MA
East end:	Route 1A in Boston, MA
Highway system
Interstate Highway System Main • Auxiliary • Business

Interstate 90 (I-90) is the longest Interstate Highway in the United States at 3,101.77 miles (4,991.81 km). It is the northernmost coast-to-coast interstate, and parallels US 20 for the most part. Its western terminus is in Seattle, Washington, at Edgar Martinez Drive S. near Safeco Field and CenturyLink Field, and its eastern terminus is in Boston, Massachusetts, at Route 1A near Logan International Airport. Interstate 90 crosses the Continental Divide over Homestake Pass just east of Butte, Montana.

East of the Wisconsin-Illinois border, much of I-90 is tolled, along the following toll roads (several of which predate the Interstate system): the Jane Addams Memorial Tollway, Chicago Skyway, Indiana Toll Road, Ohio Turnpike, New York State Thruway, and the Massachusetts Turnpike, including the Ted Williams Tunnel. It is free through downtown Chicago; Greater Cleveland and the rest of Northeast Ohio; Pennsylvania; and through brief sections near Buffalo, Albany, and Boston.

Route description[link]

Washington[link]

The western I-90 terminus is in the SoDo neighborhood of Seattle, Washington. I-90 eastbound begins at exit 2B, Edgar Martínez Drive S and 4th Avenue S. I-90 westbound exit 2B ends at Edgar Martínez Dr and 4th Ave near Safeco Field, as well as 4th Ave just north of S. Royal Broughman Way near CenturyLink Field.

The tunnel that carries Interstate 90 under the Mount Baker Ridge is on the National Register of Historic Places. The east portal of the tunnel (visible when entering Seattle from the east) is constructed as a bas relief concrete sculpture.

Interstate 90 crossing Lake Washington

Interstate 90 through Snoqualmie Pass

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.

Forty miles east of Bellevue I-90 traverses the Cascade Range's Snoqualmie Pass, elevation 3,022 feet (921 m). At mile post 137, it crosses the Columbia River on the Vantage Bridge, and after entering Spokane, Washington near mile post 279, enters Idaho 20 miles (32 km) later.

Since 1980, I-90 from Seattle to Thorp, Washington, was designated the Mountains to Sound Greenway to protect its outstanding scenic and cultural resources.^[2]

Washington Law Defining Route

The Washington section of I-90 is defined in the Revised Code of Washington (RCW 47.17.140).^[3]

Idaho[link]

The small town of Wallace, Idaho still prides itself on having what was the last stop light on I-90. Its downtown has many historical buildings, which would have been wiped out by the original planned route of the freeway, so in 1976, city leaders had the downtown placed on the National Register of Historic Places. As a result, the federal government was forced, at great expense, to reroute the freeway to the northern edge of downtown and elevate it. That section of I-90 opened in September 1991. A bicycle path is routed beneath part of that segment.

Montana[link]

I-90 near Park City, Montana

From 1995 until 1999, there was no numbered speed limit on I-90 in Montana. The speed limit was simply defined as "reasonable and prudent" as determined on a case by case basis by the Montana Highway Patrol. The speed limit in Montana is now 75 mph (120 km/h). From the west I-90 enters Montana on the summit of Lookout Pass. It passes next to Missoula and runs through Butte before crossing the continental divide just east of Butte where it goes over Homestake Pass, which is 6,329 feet (1929 m.) in elevation, the highest point for the Interstate. It passes between the Gallatin and Bridger mountain ranges over Bozeman Pass between Bozeman and Livingston. It follows the Yellowstone River from Livingston to Billings where it connects the suburbs of Laurel and Lockwood with the rest of the Billings. In Lockwood it intersects with I-94's western terminus and turns south. South of Hardin it passes the site of the Battle of the Little Bighorn (Custer's Last Stand) at Crow Agency on the Crow Indian Reservation. Montana boasts the longest stretch of I-90, ranging just over 551 miles (887 km).

Wyoming[link]

At the Montana border I-90 is a four-lane divided highway with a grass median. At Buffalo, Wyoming, I-90 intersects I-25 and goes from a north–south orientation to an east–west orientation.

Exit list[link]

County	Location	#	Destinations	Notes
Sheridan		1	Barker Road
		9	US 14 west – Ranchester, Yellowstone National Park	West end of US 14 overlap
		14	WYO 345 – Ranchester
		16	WYO 339 east
	Sheridan	20	I-90 Bus. – Sheridan
		23	US 87 south (5th Street) / WYO 336	West end of US 87 overlap
		25	US 14 east / I-90 Bus. – Clearmont	East end of US 14 overlap
		33	WYO 342 (Meade Creek Road)
		37	Prairie Dog Creek Road
Johnson		44	US 87 north	East end of US 87 overlap
		47	Shell Creek Road
		51	Lake Ridge Road
		53	Rock Creek Road
		56A	I-25 Bus. south / I-90 Bus. east – Buffalo	Eastbound exit and westbound entrance
		56B	I-25 south / US 87 south – Casper	East end of US 87 overlap
		58	US 16 / I-90 Bus. west – Buffalo, Clearmont
		65	Red Hills Road, Tipperay Road
		69	Dry Creek Road
		73	Lower Crazy Woman Road
		77	Schoonover Road
		82	Dry Creek Road
		88	Upper Powder River Road
		91	Dead Horse Road
Campbell		102	Barber Creek Road
		106	Kingsbury Road, Barlow Road
		113	Force Road, Shober Road
		116	Force Road
	Gillette	124	I-90 Bus. / WYO 50 – Gillette, Thunder Basin National Grassland
		126	WYO 59 – Thunder Basin National Grassland
		128	I-90 Bus. west / US 14 west / US 16 west – Gillette	West end of US 14/16 overlap
		129	Garner Lake Road
		132	Wyodak Road
		141	Adon Road
Crook		153	I-90 Bus. – Moorcroft
	Moorcroft	154	90 US west / 14 US east / 16 east – Moorcroft, Newcastle, Black Hills National Forest
		160	Wind Creek Road
		165	Pine Ridge Road
		172	Inyan Creek Road
		178	Beaver Road
		185	I-90 Bus. / US 14 – Sundance
	Sundance	187	WYO 585 – Sundance, Four Corners
		189	I-90 Bus. / US 14 west – Sundance	East end of US 14 overlap
		191	Moskee Road
		199	WYO 111 north – Aladdin
		205	Sand Creek Road

South Dakota[link]

Near Rapid City, South Dakota at the Wyoming border I-90 is a four lane divided highway with a grass median. In the Sioux Falls area, I-90 intersects I-29 and continues east a short distance to Minnesota. I-90 is the longest east–west thoroughfare in South Dakota. This interstate goes through Mitchell, Sioux Falls, and Rapid City. It does not go through the state capital of Pierre.

The South Dakota section of I-90 is defined at South Dakota Codified Laws § 31-4-184.^[4]

Minnesota[link]

The Minnesota section of I-90 is defined as Route 391 in Minnesota Statutes § 161.12(3).^[5]

I-90 crosses southern Minnesota from the South Dakota border near Beaver Creek, Minnesota, to the Mississippi River near La Crosse, Wisconsin. On most of its length in the state, it is close to the Iowa border and fairly parallel with it. In southeast Minnesota, it curves north to Rochester and Winona.

The wayside rest area near Blue Earth, Minnesota, is where the east-building I-90 and west-building I-90 teams linked up in 1978, thus completing the final mile and joining the 3,099.07 miles (4,987.47 km) of the interstate.^[6] Since being overlaid with bituminous paving in 2006,^[7] the original 4-foot-wide (1.2 m) gold colored cement concert line marking the completion of I-90 has been replaced with gold paint on just the shoulder portions of the roadway at the same location; plaques dedicating and describing this special segment of I-90 pavement can be found at the Blue Earth rest areas.

Wisconsin[link]

I-90 crosses Wisconsin from Minnesota to Illinois in a generally southeasterly direction. It joins I-94 in Tomah and I-39 in Portage. I-94 separates from I-90 at Madison.

I-39/90/94 from just south of Portage to Madison is the longest concurrency of three Interstate Highways in the United States.

Illinois[link]

Interstate 90 at the Belvidere oasis on the Jane Addams Memorial Tollway.

In the state of Illinois, Interstate 90 enters Illinois north of Rockford oriented north–south joined with Interstate 39. It then runs east-southeast directly to the city of Chicago. From Rockford to Interstate 294 the road is tolled and called the Jane Addams Memorial Tollway. Prior to 2007 the Jane Addams Memorial Tollway was called the Northwest Tollway. In the Chicago metropolitan area, I-90 is known by three names from O'Hare International Airport to the Indiana state line. The Kennedy Expressway runs from O'Hare to Interstate 290 and the Chicago Loop. I-90 continues running south of the Loop on part of the Dan Ryan Expressway, and then southeast onto the tolled Chicago Skyway into Indiana.

Indiana[link]

In the state of Indiana, the entirety of Interstate 90 is concurrent with the Indiana Toll Road. Interstate 90 enters from Illinois at the Chicago Skyway. It then runs to the concurrency of Interstates 80/94 east of Interstate 65, where I-80 leaves I-94 and joins with I-90. The combined I-80/90 route runs east across northern Indiana and near the southern border of Michigan to the Ohio state line.

As part of the Toll Road, I-80/90 passes to the north of South Bend and Elkhart. It also passes north of Angola at Interstate 69.

Ohio[link]

I-90 near I-71 interchange in Cleveland

The Indiana Toll Road turns into the Ohio Turnpike as it crosses the border. I-90 follows the Ohio Turnpike until Lorain (west of Cleveland), where it turns north to follow a route near the shores of Lake Erie. Originally, it was going to be parallel to, and north of, I-80/Ohio Turnpike further west to Toledo. Parts were built with an interim assignment of State Route 2. Later; that plan was abandoned, and the I-90/I-80 exit/connector was built instead; those existing parts retain the Rt. 2 designation.

In Cleveland, Interstate 90 serves as the Innerbelt at the confluence of the northern termini of Interstates 71 and 77. One of the most peculiar and hazardous stretches of Interstate 90 is the section of highway passing through downtown, known locally as Dead Man's Curve. Here, the road takes a nearly 90-degree turn.^[8] While there are plenty of large signs, flashing lights, and rumble strips alerting motorists to this turn, there have still been a large number of accidents resulting from inattentive motorists. There are plans to realign the freeway along a shallower curve within the next decade, as part of a larger project to improve the highway system in Cleveland.^[9]

The Innerbelt in Cleveland also utilizes a steel-gusset bridge of the same design as the I-35W bridge that failed in Minneapolis, Minnesota. Since September 30, 2008, two lanes in each direction of the 8-lane bridge were closed to reduce the weight load on the structure. The bridge is currently under close inspection as it has deteriorated greatly over the last few years. On October 8, 2008, the bridge was closed entirely to undergo a stress test. In May and June 2009, the bridge was closed while engineers lifted it with hydraulic jacks and moved it approximately six inches to realign it. It is largely believed that the bridge will be replaced within the next five years by a new span. Many in the Cleveland area are beginning to question the safety of the bridge, and the Ohio Department of Transportation continues to stress that the bridge is safe and if there was any imminent danger it would be permanently closed. There are plans to build a new bridge which will carry I-90 west and I-71 south. The old bridge will carry I-71 north and I-90 east.^{[citation needed]} Construction is now underway on the new bridge trusses. The project started in late 2010 and will wrap up in about 3 to 4 years. as stated by ODOT.

Pennsylvania[link]

I-90 goes from the Ohio state line through Erie, Pennsylvania, and then leaves Pennsylvania for New York. At 46.4 miles (74.67 km), it is Interstate 90's shortest intrastate length.

While not an interstate, a portion of Pennsylvania Route 5 in Erie has recently been named Pennsylvania Route 290. The purpose is to encourage travelers to use this stretch of Erie's 12th Street as a loop, connecting Interstate 79 and 90 to the Bayfront Connector and downtown Erie.

Exit list[link]

The entire route is located in Erie County, Pennsylvania

Location	#	Destinations	Notes
West Springfield	3	US 6N – West Springfield, Albion
	9	PA 18 – Lake City, Platea
	16	PA 98 – Fairview, Meadville
Erie	18	PA 832 (Sterrettania Road)
	22	I-79 – Erie, Pittsburgh	Signed as exits 22A (south) and 22B (north)
	24	US 19 (Peach Street) – Erie, Meadville
	27	PA 97 (Perry Highway)
	29	PA 8 – Mercyhurst College
	32	PA 430 – The Behrend College
	35	PA 531 (Depot Road)
	37	I-86 east – Elmira
	41	PA 89 – North East, Union City
	45	US 20 – Erie, Westfeild

New York[link]

I-90 metric sign for NY Thruway Exit 35

I-90 as AmVets Highway west of Syracuse

I-90 becomes the New York State Thruway upon entering New York. It follows the Lake Erie coast until Buffalo, where it joins the old Water Level Route until Albany. There, it takes a short detour before joining the New York State Thruway Berkshire Connector.

Almost all of the New York portion of the road is a toll road, comprising the east–west portion of the New York State Thruway mainline and part of the Berkshire Connector, 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 road roughly follows the course of the 19th-century Erie Canal for much of its length in New York State. "I-90" (operated by NYSDOT) carries Interstate 90 between the two; however, the Berkshire Section directly connects to the mainline (at Thruway interchange 21A) 6.5 miles (10.5 km) west of the point where I-90 joins it (at Thruway interchange B1).

The mileposts and exit numbers on the New York State Thruway mainline originate at the New York City line and increase northward along Interstate 87 and westward along Interstate 90. As a result, mileposts and exit numbers on the I-90 section of the Thruway mainline increase from east to west, contrary to modern practices where numbers increase from the west or south. The NYSDOT-maintained portion in between, known to locals as "I-90," does number its mileage and exits in the traditional west-to-east method. (Ironically, the NYSDOT maintained portion of I-90 is oriented geographically north–south for most of its length, so the exit numbers seem to increase from north to south.) Exit and milepost numbering starts over again when the Berkshire Section of the Thruway begins, with exit and mile numbers preceded by the letter B (Exit B1, Exit B2, Mile B1, Mile B2, and so on).

There once were two metric-only signs on the westbound New York State Thruway around Syracuse, which is about 100 miles (161 km) from Ontario. The NYS Thruway Authority decided to test metric signage, which may have briefly included an 88 km/h speed limit sign, on the Thruway. There was also a sign displaying the distance to the Interstate 81 interchange in kilometers in Dewitt. These signs are now displayed in just miles.

I-90 is one of two Interstates having a complete set of nine spur routes (190, 290, 390...890, 990) within one state, in New York, with the other being Interstate 5, in California. In addition, I-990, a short spur route near Buffalo, New York not directly connected to I-90, is the highest number given to an Interstate.

I-790 in Utica used to have a completely direct connection with I-90 at Thruway interchange 31. Various road redesign projects over the years have eventually led to this direct connection being partially severed. Traffic exiting the Thruway must use two different surface streets to reach I-790. However, it is still possible to travel from I-790 directly onto the Thruway. I-790 has some other oddities: no exit numbers, no reassurance markers, and it runs concurrent with New York State Route 5 for its entire length.

The New York section of I-90 west of the Berkshire Section of the New York Thruway is defined as Interstate Route 504 in New York Highway Law § 340-a.^[10]

Interstate 90 eastbound approaching Stockbridge and the toll plaza

Massachusetts[link]

I-90 in Massachusetts runs along the pre-Interstate era Massachusetts Turnpike, which opened on May 15, 1957, from West Stockbridge at the New York state border to Route 128.

The first section of the Boston Extension opened in September 1964 from the original terminus at Route 128 to the Allston/Brighton Tolls. The entire Boston Extension opened on February 18, 1965 continuing from the Allston/Brighton Tolls to I-93 in Downtown Boston. The new extension added 12 miles (19 km) to the MassPike's original 123.

I-90 was extended again as part of the Big Dig from its terminus at I-93 to Boston's Logan International Airport and a terminus of Route 1A in January 2003 via tunnels under the Fort Point Channel and the Ted Williams Tunnel under Boston Harbor. This extended I-90 by an additional 1.3 miles (2.1 km), shifting the eastern terminus to Route 1A.

Turnpike Doubles are permitted to travel between exit 11 and through the New York state border.

Austin, Minnesota Business Loop

History[link]

I-90 made heavy use of existing roads. The Massachusetts Turnpike, New York State Thruway, Ohio Turnpike, Indiana Toll Road, Chicago Skyway, and the Jane Addams Memorial Tollway all predate I-90 and were used for parts of its route. This also means that substantial portions of the route are not precisely to Interstate Highway standards, but they are usually close.

The popular TV sitcom Cheers was set in Boston, on the east end of I-90. When the spin-off Frasier was being developed, it was decided to set that series as far from Boston as possible, so Seattle, on the west end of I-90, was chosen as the setting.

Major intersections[link]

Interstate 5 and Interstate 90 intersecting in Seattle, Washington

• Interstate 5 in Seattle, Washington
• Interstate 405 in Bellevue, Washington
• Interstate 82 in Ellensburg, Washington
• Interstate 15 in Butte, Montana; joined for 7.65 miles (12.31 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; joined for 91.76 miles (147.67 km) until Madison, Wisconsin.
• Interstate 39 in Portage, Wisconsin; joined for about 95 miles (152 km) until Rockford, Illinois.
• Interstate 43 in Beloit, Wisconsin
• Interstate 94 in Chicago, Illinois; joined for 16.71 miles (26.89 km)
• Interstate 55 in Chicago, Illinois
• Interstate 65 in Gary, Indiana
• Interstate 94 in Lake Station, Indiana
• Interstate 80 in Lake Station, Indiana; joined for 278.40 miles (448.04 km) until Lorain, Ohio.
• Interstate 69 in Fremont, Indiana
• Interstate 75 in Toledo, Ohio
• Interstate 71 in Cleveland, Ohio
• Interstate 77 in Cleveland, Ohio
• Interstate 271 in Willoughby, Ohio
• Interstate 79 in Erie, Pennsylvania
• Interstate 86 in Erie, Pennsylvania
• Interstate 81 in Syracuse, New York
• Interstate 88 in Rotterdam, New York
• Interstate 87 in Albany, New York
• Interstate 91 in West Springfield, Massachusetts
• Interstate 291 in Chicopee, Massachusetts
• Interstate 84 in Sturbridge, Massachusetts
• Interstate 395 in Auburn, Massachusetts
• Interstate 495 in Hopkinton, Massachusetts
• Interstate 95 in Weston, Massachusetts^[11]
• Interstate 93 in Boston, Massachusetts^[12]

Auxiliary routes[link]

• 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 (not directly connected)
• Rochester, New York - I-390, I-490, I-590 (not directly connected)
• Syracuse, New York - I-690
• Utica, New York - I-790
• Schenectady, New York - I-890
• Spur to I-495 in Marlborough, Massachusetts - I-290
• Spur to Leominster, Massachusetts - I-190

I-90 is the only interstate to have a complete set of auxiliary routes (i.e., all nine possible three-digit route numbers) within a single state, that being New York.

v t e Auxiliary routes of Interstate 90 South Dakota 190 Illinois 190 290 Ohio 2901 490 New York 190 290 390 490 590 690 790 890 990 Massachusetts 190 290

References[link]

External links[link]

Wikimedia Commons has media related to: Interstate 90

• Geographic data related to Interstate 90 at OpenStreetMap
• Illinois Highway Ends: I-90
• Indiana Highway Ends: I-90
• I-90 (Greater New York Roads)

v t e Main Interstate Highways Signed 4 5 8 10 12 15 16 17 19 20 22 24 25 26 27 29 30 35 37 39 40 43 44 45 49 55 57 59 64 65 66 68 69 70 71 72 73 74 75 76 (W) 76 (E) 77 78 79 80 81 82 83 84 (W) 84 (E) 85 86 (W) 86 (E) 87 88 (W) 88 (E) 89 90 91 93 94 95 96 97 99 H-1 H-2 H-3 Unsigned A-1 A-2 A-3 A-4 PRI-1 PRI-2 PRI-3 Lists Primary Main Intrastate Suffixed Temporary Future Gaps Auxiliary Main Future Unsigned Other Standards Business Bypassed Tolled Major Interstates highlighted