Interstate 81 (I-81) is a north–south (physically northeast–southwest)
Interstate Highway
The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Hi ...
in the eastern part of the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
. Its southern terminus is at
I-40 in
Dandridge, Tennessee; its northern terminus is on
Wellesley Island, New York at the
Canadian border
The borders of Canada include:
* To the south and west: An international boundary with the United States, forming the Canada–United States border, longest shared border in the world, ; (Informally referred as the 49th parallel north which make ...
, where the
Thousand Islands Bridge connects it to
Highway 137 and ultimately to
Highway 401, the main
Ontario
Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
freeway connecting
Detroit
Detroit ( , ) is the List of municipalities in Michigan, most populous city in the U.S. state of Michigan. It is situated on the bank of the Detroit River across from Windsor, Ontario. It had a population of 639,111 at the 2020 United State ...
via
Toronto
Toronto ( , locally pronounced or ) is the List of the largest municipalities in Canada by population, most populous city in Canada. It is the capital city of the Provinces and territories of Canada, Canadian province of Ontario. With a p ...
to
Montreal
Montreal is the List of towns in Quebec, largest city in the Provinces and territories of Canada, province of Quebec, the List of the largest municipalities in Canada by population, second-largest in Canada, and the List of North American cit ...
. The major metropolitan areas along the route of I-81 include the
Tri-Cities of Tennessee;
Roanoke in
Virginia
Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...
;
Hagerstown in Maryland;
Harrisburg
Harrisburg ( ; ) is the List of capitals in the United States, capital city of the Commonwealth (U.S. state), U.S. commonwealth of Pennsylvania and the county seat, seat of Dauphin County, Pennsylvania, Dauphin County. With a population of 50, ...
and the
Wyoming Valley
The Wyoming Valley is a historic industrialized region of Northeastern Pennsylvania. The region is historically notable for its influence in helping fuel the American Industrial Revolution with its many anthracite coal mines. As a metropolitan ar ...
in
Pennsylvania
Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
; and
Binghamton and
Syracuse in New York.
I-81 largely traces the paths created down the length of the
Appalachian Mountains
The Appalachian Mountains, often called the Appalachians, are a mountain range in eastern to northeastern North America. The term "Appalachian" refers to several different regions associated with the mountain range, and its surrounding terrain ...
through the
Great Appalachian Valley by migrating animals,
indigenous peoples
There is no generally accepted definition of Indigenous peoples, although in the 21st century the focus has been on self-identification, cultural difference from other groups in a state, a special relationship with their traditional territ ...
, and early settlers. It also follows a major corridor for troop movements during the
Civil War
A civil war is a war between organized groups within the same Sovereign state, state (or country). The aim of one side may be to take control of the country or a region, to achieve independence for a region, or to change government policies.J ...
. These trails and roadways gradually evolved into
US Route 11 (US 11); I-81 parallels much of the older US 11. Being mostly rural in nature, I-81 is heavily used as a trucking corridor and is often used as a bypass of busier and more congested Interstates to the east such as
I-95; for this reason, it is also used heavily by
drug
A drug is any chemical substance other than a nutrient or an essential dietary ingredient, which, when administered to a living organism, produces a biological effect. Consumption of drugs can be via insufflation (medicine), inhalation, drug i ...
and
human traffickers, as it is less monitored by
law enforcement
Law enforcement is the activity of some members of the government or other social institutions who act in an organized manner to enforce the law by investigating, deterring, rehabilitating, or punishing people who violate the rules and norms gove ...
than I-95. This led to the
Federal Bureau of Investigation
The Federal Bureau of Investigation (FBI) is the domestic Intelligence agency, intelligence and Security agency, security service of the United States and Federal law enforcement in the United States, its principal federal law enforcement ag ...
(FBI) forming a taskforce to combat the issue in 2017.
The I-81 Corridor Coalition, a six-state coalition, was organized to handle issues along I-81, such as truck traffic and
air pollution
Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...
; the commission meets annually. I-81 is part of the fastest route between the
capital of the US (
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...
) and the capital of
Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
(
Ottawa
Ottawa is the capital city of Canada. It is located in the southern Ontario, southern portion of the province of Ontario, at the confluence of the Ottawa River and the Rideau River. Ottawa borders Gatineau, Gatineau, Quebec, and forms the cor ...
).
Route description
I-81 is part of the
National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the
Federal Highway Administration
The Federal Highway Administration (FHWA) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs, the Federal-aid Highway Program a ...
(FHWA).
, -
,
TN , ,
, -
,
VA , ,
, -
,
WV , ,
, -
,
MD , ,
, -
,
PA , ,
, -
,
NY , ,
, -
, Total , ,
Tennessee
I-81 begins in Tennessee at
I-40 in
Dandridge, a route that connects to
Knoxville
Knoxville is a city in Knox County, Tennessee, United States, and its county seat. It is located on the Tennessee River and had a population of 190,740 at the 2020 United States census. It is the largest city in the East Tennessee Grand Division ...
to the west and
Asheville to the east. I-81 meets
I-26 and
US 23, which go to
Kingsport and
Johnson City. At milemarker 75, I-81 leaves Tennessee and enters Virginia.
Virginia
I-81 in Virginia is largely a rural route with brief concurrencies with
I-77 and
I-64. The route parallels the Appalachian Mountains for much of its route through Tennessee and Virginia, serving such cities as the
twin cities
Twin cities are a special case of two neighboring cities or urban centres that grow into a single conurbation – or narrowly separated urban areas – over time. There are no formal criteria, but twin cities are generally comparable in stat ...
of Bristol,
Tennessee
Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...
and
Virginia
Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...
;
Wytheville;
Roanoke;
Christiansburg;
Lexington;
Staunton;
Harrisonburg; and
Winchester
Winchester (, ) is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government Districts of England, district, at the western end of the South Downs N ...
. In Harrisonburg, I-81 cuts through
James Madison University
James Madison University (JMU, Madison, or James Madison) is a public university, public research university in Harrisonburg, Virginia, United States. Founded in 1908, the institution was renamed in 1938 in honor of the fourth president of the ...
.
It parallels its older counterpart,
US 11, for its entire length in Virginia.
West Virginia
I-81 briefly enters the
Eastern Panhandle of West Virginia for about , serving the city of
Martinsburg. The entire routing is in
Berkeley County and serves the
Eastern WV Regional Airport. The
West Virginia
West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...
segment was completed in 1966 and there have been no realignments since.
Maryland
In
Maryland
Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...
, the Interstate Highway runs from the
West Virginia
West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...
state line at the
Potomac River
The Potomac River () is in the Mid-Atlantic (United States), Mid-Atlantic region of the United States and flows from the Potomac Highlands in West Virginia to Chesapeake Bay in Maryland. It is long,U.S. Geological Survey. National Hydrography D ...
in
Williamsport north to the
Pennsylvania
Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...
state line near
Maugansville. I-81 is the primary north–south Interstate Highway in
Washington County, connecting
Hagerstown with
Chambersburg and
Harrisburg
Harrisburg ( ; ) is the List of capitals in the United States, capital city of the Commonwealth (U.S. state), U.S. commonwealth of Pennsylvania and the county seat, seat of Dauphin County, Pennsylvania, Dauphin County. With a population of 50, ...
to the north and
Martinsburg,
Winchester
Winchester (, ) is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government Districts of England, district, at the western end of the South Downs N ...
, and
Roanoke to the south.
It is the shortest mainline Interstate in Maryland and contains the shortest portion of I-81 of all six states through which the Interstate highway passes. The Interstate was dedicated as Maryland Veterans Memorial Highway in 1987.
I-81 passes through the state of Maryland at one of its narrowest points, the "Hub City" of
Hagerstown where it intersects with a large number of other routes, most notably
I-70.
Hagerstown Regional Airport is served by this Interstate Highway.
Pennsylvania
I-81 forms a major north–south corridor through the state of Pennsylvania, serving the boroughs of
Chambersburg and
Carlisle
Carlisle ( , ; from ) is a city in the Cumberland district of Cumbria, England.
Carlisle's early history is marked by the establishment of a settlement called Luguvalium to serve forts along Hadrian's Wall in Roman Britain. Due to its pro ...
, where it meets the
Pennsylvania Turnpike (
I-76) but does not directly interchange with it (motorists must use US 11 to connect). Around the state capital of
Harrisburg
Harrisburg ( ; ) is the List of capitals in the United States, capital city of the Commonwealth (U.S. state), U.S. commonwealth of Pennsylvania and the county seat, seat of Dauphin County, Pennsylvania, Dauphin County. With a population of 50, ...
, the route forms the northern section of Pennsylvania's
Capital Beltway
The Capital Beltway, designated as Interstate 495 (I-495) for its entire length, is an List of auxiliary Interstate Highways, auxiliary Interstate Highway in the Washington metropolitan area. The Ring road, beltway encircles Washington, D.C., ...
. The route then travels northeast toward the
Wyoming Valley
The Wyoming Valley is a historic industrialized region of Northeastern Pennsylvania. The region is historically notable for its influence in helping fuel the American Industrial Revolution with its many anthracite coal mines. As a metropolitan ar ...
, where it serves the cities of
Wilkes-Barre and
Scranton(as well as meeting the PA Turnpike's Northeast Extension), then heads north through the
Endless Mountains region toward the state line.
New York

In New York, I-81 crosses the
Pennsylvania state line southeast of
Binghamton. The freeway runs north–south through
Central New York, serving the cities of Binghamton,
Syracuse, and
Watertown. It passes through the
Thousand Islands in its final miles and crosses two bridges, both part of the series of bridges known as the
Thousand Islands Bridge. South of Watertown, I-81 closely parallels
US 11, the main north–south highway in Central New York prior to the construction of I-81. At Watertown, US 11 turns northeastward to head across New York's
North Country while I-81 continues on a generally northward track to the Canadian border. From there, the road continues into the province of
Ontario
Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...
as
Highway 137, a short route leading north to the nearby
Highway 401.
History
I-81 roughly parallels the
Great Indian Warpath
The Great Indian Warpath (GIW)—also known as the Great Indian War and Trading Path, or the Seneca Trail—was part of the network of trails in eastern North America developed and used by Native Americans in the United States, Native Americans w ...
, an old Indian trail that connected New York to the
Piedmont
Piedmont ( ; ; ) is one of the 20 regions of Italy, located in the northwest Italy, Northwest of the country. It borders the Liguria region to the south, the Lombardy and Emilia-Romagna regions to the east, and the Aosta Valley region to the ...
region of the southeastern United States via Virginia and West Virginia. A series of roads linking Virginia to Maryland through Martinsburg were present on maps as early as 1873. New York was originally served by
New York State Route 2 (NY 2), a road built in 1924; NY 2 was replaced by
US 11 in 1927. A highway that largely followed the path of US 11 was built and became known as the
Penn-Can Highway. On August 14, 1957, the highway was redesigned as I-81. In New York, the first segments of what would become I-81 were begun in 1954.
In Maryland, the Interstate was begun with the Hagerstown Bypass in the mid-1950s. After several bouts of expansion, the freeway was completed from US 40 (now
Maryland Route 144
Maryland Route 144 (MD 144) is a collection of state highways in the U.S. state of Maryland. These highways are sections of old alignment of U.S. Route 40 in Maryland, U.S. Route 40 (US 40) between Cumberland, Maryland, Cumberland and Baltimo ...
D 144 to the Pennsylvania state line in 1958 and marked as I-81 in 1959. Bidding on contracts in West Virginia opened in July 1958. In Virginia, the first Interstate hearing was held in February 1957. At the end of 1957, construction began on a stretch near
Buchanan, Virginia. A section of the Interstate opened in 1959. A stretch in
Harrisonburg was opened as well. By late 1963, in Virginia were open.
The first statewide segment to be completed was that of West Virginia, which was finished in 1966. The section opened on October 19, 1966. In western Maryland, various parts of I-81 were built in the early 1960s, and the remainder of the highway south to the Potomac River was under construction by 1965 and opened in 1966.
Since then, I-81 in Maryland has remained largely unchanged. In Tennessee by 1965, of the of Interstate Highways were completed. Construction was expected to be finished in 1969, but a large portion of the work would not be completed until 1974, and most of the road was open by December 1974. The final major segment of the Interstate in the north to be built was a section in New York, opened in October 1968. That same year, work in Pennsylvania was completed. The road would not be completely built in Tennessee until August 1975. Construction on parts in Virginia dragged on until it was finished in July 1987.
The segment in New York cost $270 million (equivalent to $ in ) to build.
Major intersections
;Tennessee
* near
Dandridge, northeast of
Knoxville
Knoxville is a city in Knox County, Tennessee, United States, and its county seat. It is located on the Tennessee River and had a population of 190,740 at the 2020 United States census. It is the largest city in the East Tennessee Grand Division ...
* at the
White Pine–
Morristown line
* in
Mosheim
* in
Kingsport
* in
Bristol
Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...
;Virginia
[
* in ]Bristol
Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...
. I-81/US 58 travels concurrently to east of Abingdon
* in Bristol
* in Bristol
* east of Abingdon
* at various locations
* in Wytheville. I-81/US 52 travels concurrently to Fort Chiswell
* in Wytheville. The highways travel concurrently to Fort Chiswell.
* in Christiansburg
* in Roanoke
* southeast of Lexington
* east of Lexington. The highways travel concurrently to Staunton.
* in Peyton
* in Harrisonburg
* New Market
* southwest of Middletown
* in Winchester
Winchester (, ) is a City status in the United Kingdom, cathedral city in Hampshire, England. The city lies at the heart of the wider City of Winchester, a local government Districts of England, district, at the western end of the South Downs N ...
;West Virginia[
* north-northeast of Falling Waters
;Maryland][
* in Williamsport
* in Halfway
* in Hagerstown
;Pennsylvania][
* Chambersburg
* north of Enola
* in ]Harrisburg
Harrisburg ( ; ) is the List of capitals in the United States, capital city of the Commonwealth (U.S. state), U.S. commonwealth of Pennsylvania and the county seat, seat of Dauphin County, Pennsylvania, Dauphin County. With a population of 50, ...
. I-81/US 322 concurrent throughout Harrisburg.
* in Harrisburg
* near Jonestown
The Peoples Temple Agricultural Project, better known by its informal name "Jonestown", was a remote settlement in Guyana established by the Peoples Temple, an American religious movement under the leadership of Jim Jones. Jonestown became in ...
* west of Tremont
* near Hazleton
* in Dupont
Dupont, DuPont, Du Pont, duPont, or du Pont may refer to:
People
* Dupont (surname) Dupont, also spelled as DuPont, duPont, Du Pont, or du Pont is a French surname meaning "of the bridge", historically indicating that the holder of the surname re ...
(near Pittston
Pittston is a city in Luzerne County, Pennsylvania, United States. The city lies in the Wyoming Valley on the east side of the Susquehanna River and on the south side of the Lackawanna River. It is approximately midway between Wilkes-Barre, Pen ...
)
* in Dunmore
* in Clarks Summit
;New York[
* in Binghamton
* in Binghamton
* in LaFayette
* in Syracuse
* in Syracuse
* in North Syracuse
* in ]Cicero
Marcus Tullius Cicero ( ; ; 3 January 106 BC – 7 December 43 BC) was a Roman statesman, lawyer, scholar, philosopher, orator, writer and Academic skeptic, who tried to uphold optimate principles during the political crises tha ...
* in Adams
* in Watertown
* ; freeway ends at Canada–US border ( Thousand Islands Bridge)
Auxiliary routes
I-81 has six related, auxiliary Interstate Highways that connect the main freeway to downtowns and other cities. I-381 runs , connecting Bristol, Virginia
Bristol is an independent city (United States), independent city in the Commonwealth (U.S. state), Commonwealth of Virginia. As of the 2020 United States census, 2020 census, the population was 17,219. It is the Twin cities (geographical proxi ...
, to I-81. I-581 is a spur that connects Roanoke, Virginia
Roanoke ( ) is an Independent city (United States), independent city in Virginia, United States. It lies in Southwest Virginia, along the Roanoke River, in the Blue Ridge Mountains, Blue Ridge range of the greater Appalachian Mountains. Roanok ...
, to I-81. It is proposed to be overtaken by I-73. Pennsylvania Route 581
The Capital Beltway is a ring road, beltway surrounding Harrisburg, Pennsylvania, Harrisburg, Pennsylvania, in the United States. It is concurrency (road), co-designated as Interstate 81 in Pennsylvania, Interstate 81 (I-81), Interstate 83 ...
(PA 581) connects Harrisburg, Pennsylvania
Harrisburg ( ; ) is the capital city of the U.S. commonwealth of Pennsylvania and the seat of Dauphin County. With a population of 50,099 as of 2020, Harrisburg is the ninth-most populous city in Pennsylvania. It is the larger of the two pr ...
, to I-81. It runs . I-481 serves as an eastern bypass of Syracuse, New York
Syracuse ( ) is a City (New York), city in and the county seat of Onondaga County, New York, United States. With a population of 148,620 and a Syracuse metropolitan area, metropolitan area of 662,057, it is the fifth-most populated city and 13 ...
. NY 481 is a northwestern extension of I-481 that ends in Oswego. I-781 extends for , that connects Fort Drum, New York, to the Interstate. NY 281 is a north–south state highway
A state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually a road that is either Route number, numbered or maintained by a sub-national state or province. A road numbered ...
in Central New York in the US that extends for across Cortland and Onondaga counties, roughly paralleling I-81 and connecting at both ends.
I-181 was a offshoot of I-81, linking to Kingsport, Tennessee. It was decommissioned in August 2005 when I-26 took over I-181's entire length. I-281 was replaced in January 1970 by I-481. I-81E was replaced by the current I-380.
References
External links
*
Thousand Islands Bridge System
showing the bridges and connections at the northern terminus
a Federal Highway Administration report.
{{Authority control
81