Interstate 81 (I-81) is a north–south Interstate Highway, stretching from Dandridge, Tennessee, northeast to Fisher's Landing, New York, at the Canada–United States border. In Pennsylvania, I-81 runs for 232.76 miles (374.59 km) from the Maryland state line northeast to the New York state line near Hallstead and is called the American Legion Memorial Highway. The interstate enters the state near the borough of Greencastle, serving the boroughs of Chambersburg and Carlisle, before reaching Harrisburg, the capital. After that, it climbs into the Pocono Mountains to run through the Wyoming Valley, then exits into New York. It is the longest north–south Interstate in Pennsylvania.^[2]

Quick Facts Route information, Length ...

Interstate 81
American Legion Memorial Highway
I-81 highlighted in red
Route information
Maintained by PennDOT
Length	232.76 mi[1] (374.59 km)
NHS	Entire route
Major junctions
South end	I-81 at the Maryland state line near Greencastle
Major intersections	US 30 in Chambersburg US 11 in Carlisle PA 581 near Camp Hill US 22 / US 322 in Harrisburg I-83 / US 322 in Colonial Park I-78 in Lickdale I-80 near Hazleton PA 309 in Wilkes-Barre I-84 / I-380 / US 6 in Dunmore I-476 / Penna Turnpike NE Extension / US 6 / US 11 near Scranton
North end	I-81 at the New York state line near Hallstead
Location
Country	United States
State	Pennsylvania
Counties	Franklin, Cumberland, Dauphin, Lebanon, Schuylkill, Luzerne, Lackawanna, Susquehanna
Highway system
Interstate Highway System Main Auxiliary Suffixed Business Future Pennsylvania State Route System Interstate US State Scenic Legislative
← PA 80 → PA 81

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I-81 enters Pennsylvania at the Maryland state line about 13 miles (21 km) south of Chambersburg; it also has its first exit at the state line, junctioning with Pennsylvania Route 163 (PA 163) there. In Chambersburg at exit 16, it meets U.S. Route 30 (US 30; the Chambersburg Pike to Gettysburg). About a mile (1.6 km) north of Carlisle at exit 52, it meets US 11, which connects to the Pennsylvania Turnpike/I-76 (halfway between Philadelphia and Pittsburgh), since I-81 has no direct interchange with I-76.^[3][4] The stretch of US 11 connecting I-81 to I-76 is known locally as the "Miracle Mile" since it contains plenty of traveler services including restaurants, gas stations, lodging, truck stops, and shops.^[5] From here, I-81 travels in an almost precisely east–west direction for the next 37 miles (60 km) (until exit 89). At exit 59, it has an interchange with the western terminus of PA 581. I-81 becomes the Capital Beltway from exit 59 to exit 70. At exit 67, the road comes to a stack interchange with US 22 and US 322; US 322 merges with I-81. Exit 70 is the eastern terminus of the US 322 concurrency and the northern terminus of I-83 and is located in Colonial Park. For the entire segment between the Mason–Dixon line and I-78, I-81 runs through the Great Valley. North of Harrisburg between I-83/US 322 and I-78, the highway passes near Hershey and Fort Indiantown Gap.^[3][4]

At milemarker 89, I-81 meets the western terminus of I-78; I-78 picks up the eastward route through the Great Valley and heads toward Allentown and New York City, while I-81 turns back northward, cutting through Blue Mountain at Swatara Gap. From milemarkers 141 to 146, I-81 passes near the city of Hazleton. At exit 151, I-81 meets I-80. As motorists enter Wilkes-Barre at milemarker 165, I-81 merges with PA 309 for five miles (8.0 km). At exit 175, I-81 meets with PA 315, which connects to I-476 (Pennsylvania Turnpike Northeast Extension). In Scranton at milemarker 185, there is a short freeway called the President Biden Expressway, which heads into downtown Scranton. At milemarker 187, I-81 is at the Throop Dunmore Interchange, which consists of I-84, I-380, and US 6. US 6 merges with I-81 for seven miles (11 km) from milemarkers 187 to 194. At milemarker 194 is the northern terminus of I-476. The last exit in Pennsylvania is exit 230, which is PA 171 near Hallstead. I-81 reaches the New York state line four miles (6.4 km) north of exit 230.^[3][4]

A toll highway along the present-day I-81 corridor through Pennsylvania was planned in the 1950s. The section from Scranton to the New York state line was planned as a continuation of the Northeast Extension of the Pennsylvania Turnpike. A new extension of the turnpike between Harrisburg and Scranton was also proposed. After the Federal-Aid Highway Act of 1956 was passed, plans were changed to build a free Interstate Highway rather than a toll road. The first section to be built ran from PA 347 in Dunmore to US 11 in northern Scranton, this section opening in 1960. All of I-81 in Pennsylvania was completed by the 1970s. Construction cost nearly $443 million (equivalent to $2.68 billion in 2023^[6]).^[2]

On May 9, 2013, a tanker crashed and caught fire at the interchange between I-81 and US 22/US 322 in Harrisburg. The fire damaged the bridges carrying westbound US 22/US 322 and a ramp over I-81. At least one of those bridges, carrying US 22 eastbound over I-81 and several ramps, and possibly another, the ramp carrying traffic from I-81 northbound to US 22/US 322 westbound, would have to be demolished and replaced. The fire resulted in about 10 miles (16 km) of I-81 being closed in both directions, with traffic being diverted along the southern portion of the Capital Beltway.^[7][8] The highway was not fully reopened until the evening of May 13.^[9]

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