Interstate 80

I-80 begins at an interchange with US Route 101 (US 101) in San Francisco and then crosses the San Francisco–Oakland Bay Bridge into Oakland. It then heads northeast through Vallejo, Sacramento, and the Sierra Nevada before crossing into Nevada.

A portion of the route through Pinole involved the experimental transplantation of the rare species Santa Cruz tarplant in the right-of-way.

In Nevada, I-80 traverses the northern portion of the state. The freeway serves the Reno metropolitan area, and it also goes through the towns of Fernley, Lovelock, Winnemucca, Battle Mountain, Elko, Wells, and West Wendover on its way through the state.

The Nevada portion of I-80 follows the paths of the Truckee and Humboldt rivers, which have been used as a transportation corridor since the California Gold Rush of the 1840s. The Interstate also follows the historical routes of the California Trail, first transcontinental railroad, and Feather River Route throughout portions of the state. I-80 in Nevada closely follows, and at many points directly overlaps, the original route of the Victory Highway, State Route 1 (SR 1), and US 40.

After crossing Utah's western border in Wendover, I-80 crosses the desolate Bonneville Salt Flats west of the Great Salt Lake. The longest stretch between exits on an Interstate Highway is located between Wendover and Knolls, with 37.4 miles (60.2 km) between those exits.[2] This portion of I-80, crossing the Great Salt Lake Desert, is extremely flat and straight, dotted with large warning signs about driver fatigue and drowsiness.

East of the salt flats, I-80 passes the southern edge of Great Salt Lake and continues on through Salt Lake City, where it merges with I-15 for three miles (4.8 km) before entering the Wasatch Range east of the city. It ascends Parleys Canyon and passes within a few miles of Park City as it follows a route through the mountains toward the junction with the eastern terminus of the western section of I-84. From the junction it continues up Echo Canyon and on toward the border with Wyoming, near Evanston.

The route of the Utah section of I-80 is defined in Utah Code Annotated § 72-4-113(10).[3]

In Wyoming, I-80 reaches its maximum elevation of 8,640 feet (2,630 m) above sea level[4] at Sherman Summit, near Buford, which, at 8,000 feet (2,400 m), is the highest community on I-80. Farther west in Wyoming, the Interstate passes through the dry Red Desert and over the Continental Divide. In a way, the highway crosses the Divide twice, since two ridges of the Rocky Mountains split in Wyoming, forming the endorheic Great Divide Basin, from which surface water cannot drain but can only evaporate.

I-80 enters Nebraska west of Bushnell. The western portion of I-80 in Nebraska runs very close to the state of Colorado, without entering the state. The intersection of I-76 and I-80 is visible from the Colorado–Nebraska state line. From its intersection with I-76 to Grand Island, I-80 lies in the valley of the South Platte River and the Platte River.

The longest straight stretch of Interstate anywhere in the Interstate Highway System is the approximately 72 miles (116 km) of I-80 occurring between exit 318 in the Grand Island area and milemarker 390 near Lincoln. Along this length, the road does not vary from an ideally straight line by more than a few yards. After Lincoln, I-80 turns northeast toward Omaha. It then crosses the Missouri River in Omaha to enter the state of Iowa. Part of I-80 in Nebraska is marked as a Blue Star Memorial Highway.

I-80 is the longest Interstate Highway in Iowa. It extends from west to east across the central portion of the state through the population centers of Council Bluffs, Des Moines, and the Quad Cities.[5] It enters the state at the Missouri River in Council Bluffs and heads east through the southern Iowa drift plain. In the Des Moines metropolitan area, I-80 meets up with I-35 and the two routes bypass Downtown Des Moines together while I-235 proceeds straight through the metro and rejoins both on the far side. In Ankeny, the Interstates split and I-80 continues east. On the west edge of the Iowa City metropolitan area, it intersects I-380, a segment of the Avenue of the Saints. Northwest of the Quad Cities in Walcott is Iowa 80, the world's largest truckstop. I-80 passes along the northern edge of Davenport and Bettendorf and leaves Iowa via the Fred Schwengel Memorial Bridge over the Mississippi River into Illinois. The majority of the highway runs through farmland,[5] yet roughly a third of Iowa's population live along the I-80 corridor.[6]

In Illinois, I-80 runs from the Fred Schwengel Memorial Bridge across the Mississippi River south to an intersection with I-74. It then runs east across north-central Illinois just north of the Illinois River to Joliet. I-80 continues east through the southern suburbs of Chicago and joins I-94 just before entering Indiana.

In Indiana, I-80 runs concurrently with another Interstate Highway for its entire length. It runs with I-94 on the Borman Expressway from the Illinois state line to Lake Station, Indiana, then with I-90 on the Indiana Toll Road from Lake Station to the Ohio state line.

Between La Porte and the Toledo metropolitan area, I-80/I-90 is located within 10 miles (16 km) of the Michigan state line but does not enter that state. From the State Road 9 (SR 9) and I-80/I-90 interchange, the sign marking the Indiana–Michigan state line is visible. I-80/I-90 passes through the South Bend–Mishawaka metropolitan area, passing the University of Notre Dame and the University Park Mall, intersecting with the St. Joseph Valley Parkway. At another point in northern Indiana, I-80/I-90 comes within about 200 yards (180 m) of the Michigan border.[7]

In Ohio, I-80/I-90 enters from the Indiana Toll Road and immediately becomes the Ohio Turnpike. The two Interstates cross rural northwest Ohio and run just south of the Toledo metropolitan area. In Rossford, the turnpike intersects I-75 in an area known as the Crossroads of America. This intersection is one of the largest intersections of three Interstate Highways in the United States.

In Elyria Township, just west of Cleveland, I-90 splits from I-80, leaving the turnpike and running northeast as a freeway. I-80 runs east-southeast through the southern suburbs of Cleveland. Just northwest of Youngstown, the Ohio Turnpike continues southeast as I-76, while I-80 exits the turnpike and runs east to the north of Youngstown, entering Pennsylvania south of Sharon, Pennsylvania.

In Pennsylvania, I-80 is the main east–west freeway through the central part of the state. It runs from the Ohio state line near Sharon to the Delaware Water Gap Toll Bridge over the Delaware River and is called the "Z.H. Confair Memorial Highway".

It traverses the extreme northern section of Greater Pittsburgh. I-80 serves as the western terminus for I-376 which connects it to Pittsburgh International Airport and on to Downtown Pittsburgh and suburban Pittsburgh. I-80 intersects I-79, which connects with Erie (about 75 miles (121 km) to the north) and Pittsburgh (about 55 miles (89 km) to the south). Further east, I-99 connects with State College and Altoona. A spur from I-80 (I-180) runs to Williamsport. Upon entering the Pocono Mountains region, I-80 meets I-81, connecting Syracuse, New York, and Harrisburg, and I-476 which connects with Scranton, Wilkes-Barre, Allentown, and Philadelphia. Another spur (I-380) runs to Scranton.

In Clearfield County, I-80 reaches its highest elevation east of the Mississippi River, 2,250 feet (690 m), although other Interstate Highways east of the Mississippi, including I-26 in North Carolina and Tennessee, reach higher elevations.

In 2007, the Pennsylvania Turnpike Commission (PTC), combined with state legislature Act No. 44, initiated plans to enact a tolling system on the entire span of I-80 throughout the commonwealth of Pennsylvania. On October 15, 2007, the Pennsylvania Department of Transportation (PennDOT) and the PTC signed a 50-year lease agreement, which would allow the PTC to maintain and, eventually, toll I-80.[8] However, the application for a toll was rejected by the Federal Highway Administration (FHWA).[9]

I-80 does not enter New York City. Once the I-95/New Jersey Turnpike was extended in 1971 from its former terminus at US 46 in Ridgefield to I-80 in Teaneck, the section from Teaneck to Fort Lee was resigned as I-95, and it is the latter roadway that enters New York City via the George Washington Bridge. I-80's designated end (as per signage and New Jersey Department of Transportation (NJDOT) documents) is four miles (6.4 km)[10] short of New York City in Teaneck, before the Degraw Avenue overpass. There, signs designate the end of I-80 and the beginning of I-95/New Jersey Turnpike northbound.

One section of I-80 running from Netcong to Denville was constructed in 1958.

John McPhee described the geology revealed by the building of I-80 in a series of books on the formation of the continent of North America, books that were published between 1981 and 1993 and collected in a one-volume edition in 1998 Annals of the Former World which won a Pulitzer Prize in 1999. In "Basin and Range" (1981), he described how the idea emerged in a conversation with Princeton geologist Kenneth S. Deffeyes: "What about Interstate 80, I asked him. It goes the distance. How would it be? 'Absorbing,' he said. And he mused aloud: After 80 crosses the Border Fault, it pussyfoots along on morainal till that levelled up the fingers of the foldbelt hills. It does a similar dance with glacial debris in parts of Pennsylvania. It needs no assistance on the craton. It climbs a ramp to the Rockies and a fault-block staircase up the front of the Sierra. It is geologically shrewd. It was the route of animal migrations, and of human history that followed. It avoids melodrama, avoids the Grand Canyons, the Jackson Holes, the geologic operas of the country, but it would surely be a sound experience of the big picture, of the history, the construction, the components of the continent."[13]