Interstate 81 marker

Interstate 81

I-81 highlighted in red
Route information
Length855.02 mi[1] (1,376.02 km)
NHSEntire route
Major junctions
South end I-40 in Dandridge, TN
Major intersections
North end Highway 137 on Thousand Islands Bridge at Wellesley Island, NY/Hill Island, ON
CountryUnited States
StatesTennessee, Virginia, West Virginia, Maryland, Pennsylvania, New York
Highway system

Interstate 81 (I-81) is a north–south (physically northeast–southwest) Interstate Highway in the eastern part of the United States. Its southern terminus is at I-40 in Dandridge, Tennessee; its northern terminus is on Wellesley Island, New York at the Canadian border, where the Thousand Islands Bridge connects it to Highway 137 and ultimately to Highway 401, the main Ontario freeway connecting Detroit via Toronto to Montreal. The major metropolitan areas along the route of I-81 include the Tri-Cities of Tennessee; Roanoke in Virginia; Harrisburg and the Wyoming Valley in Pennsylvania; and Syracuse in New York.

I-81 largely traces the paths created down the length of the Appalachian Mountains through the Great Appalachian Valley by migrating animals, indigenous peoples, and early settlers. It also follows a major corridor for troop movements during the Civil War.[2] These trails and roadways gradually evolved into US Route 11 (US 11); I-81 parallels much of the older US 11.[3] 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 and human traffickers, as it is less monitored by law enforcement than I-95. This led to the Federal Bureau of Investigation (FBI) forming a taskforce to combat the issue in 2017.[4][5]

The I-81 Corridor Coalition, a six-state coalition, was organized to handle issues along I-81, such as truck traffic and air pollution; the commission meets annually.[6] I-81 is part of the fastest route between the capital of the US (Washington, D.C.) and the capital of Canada (Ottawa) and Mexico (Mexico City).[7][8]

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 (FHWA).[9]

  mi[1] km
TN 75.66 121.76
VA 324.92 522.91
WV 26.00 41.84
MD 12.08 19.44
PA 232.76 374.59
NY 183.60 295.48
Total 855.02 1,376.02


Main article: Interstate 81 in Tennessee

I-81 begins in Tennessee at I-40 in Dandridge, a route that connects to Knoxville 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.


Main article: Interstate 81 in Virginia

I-81 looking southbound near milepost 245 in Harrisonburg, 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 of Bristol, Tennessee and Virginia; Wytheville; Roanoke; Christiansburg; Lexington; Staunton; Harrisonburg; and Winchester. In Harrisonburg, I-81 cuts through James Madison University.[10] It parallels its older counterpart, US 11, for its entire length in Virginia.[11]

West Virginia

Main article: Interstate 81 in West Virginia

Northbound on I-81 just after entering West Virginia

I-81 briefly enters the Eastern Panhandle of West Virginia for about 26 miles (42 km), serving the city of Martinsburg. The entire routing is in Berkeley County and serves the Eastern WV Regional Airport. The West Virginia segment was completed in 1966 and there have been no realignments since.


Main article: Interstate 81 in Maryland

View north along I-81 just north of exit 5 at Halfway Boulevard in Halfway, Maryland

In Maryland, the Interstate Highway runs 12.08 miles (19.44 km) from the West Virginia state line at the Potomac River in Williamsport north to the Pennsylvania state line near Maugansville. I-81 is the primary north–south Interstate Highway in Washington County, connecting Hagerstown with Chambersburg and Harrisburg to the north and Martinsburg, Winchester, and Roanoke to the south.[12] 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.[13] 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.[12]


Main article: Interstate 81 in Pennsylvania

I-81 northbound at western terminus of I-78 in Lebanon County, Pennsylvania

I-81 forms a major north–south corridor through the state of Pennsylvania, serving the boroughs of Chambersburg and Carlisle, 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, the route forms the northern section of Pennsylvania's Capital Beltway. The route then travels northeast toward the Wyoming Valley, where it serves the cities of Wilkes-Barre and Scranton, then heads north through the Endless Mountains region toward the state line.

New York

Main article: Interstate 81 in New York

I-81 at I-690 in downtown Syracuse

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 as Highway 137, a short route leading north to the nearby Highway 401.[14]


I-81 roughly parallels the Great Indian Warpath, an old Indian trail that connected New York to the Piedmont via Virginia and West Virginia.[15] A series of roads linking Virginia to Maryland through Martinsburg were present on maps as early as 1873.[16] New York was originally served by New York State Route 2 (NY 2), a road built in 1924;[17] 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.[18] On August 14, 1957, the highway was redesigned as I-81.[19] In New York, the first segments of I-81 were begun in 1954.[20] In Maryland, the Interstate was begun with the Hagerstown Bypass in the mid-1950s.[21] After several bouts of expansion, the freeway was completed from US 40 (now Maryland Route 144 [MD 144]) to the Pennsylvania state line in 1958[22] and marked as I-81 in 1959.[23] Bidding on contracts in West Virginia opened in July 1958.[24] In Virginia, the first Interstate hearing was held in February 1957. At the end of 1957, construction began on a one-mile (1.6 km) stretch near Buchanan, Virginia. A four-mile (6.4 km) section of the Interstate opened in 1959. A stretch in Harrisonburg was opened as well. By late 1963, 85 miles (137 km) in Virginia were open.[25]

The first statewide segment to be completed was that of West Virginia, which was finished in 1966. The section opened on October 19, 1966.[26] 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[27] and opened in 1966.[13] Since then, I-81 in Maryland has remained largely unchanged. In Tennessee by 1965, 336 (541) of the 997 miles (1,605 km) of Interstate Highways were completed. Construction was expected to be finished in 1969,[28] but a large portion of the work would not be completed until 1974, and most of the road was open by December 1974.[29] The final major segment of the Interstate in the north to be built was a 17-mile (27 km) section in New York, opened in October 1968.[30] That same year, work in Pennsylvania was completed.[31] The road would not be completely built in Tennessee until August 1975.[32] Construction on parts in Virginia dragged on until it was finished in July 1987.[25] The segment in New York cost $270 million (equivalent to $621 million in 2023[33]) to build.[20]

Major intersections

New York


Auxiliary routes

I-81 has six related, auxiliary Interstate Highways that connect the main freeway to downtowns and other cities. I-381 runs 1.5 miles (2.4 km), connecting Bristol, Virginia, to I-81.[35] I-581 is a 6.35-mile-long (10.22 km) spur that connects Roanoke, Virginia, to I-81. It is proposed to be overtaken by I-73.[36] Pennsylvania Route 581 (PA 581) connects Harrisburg, Pennsylvania, to I-81. It runs 7.36 miles (11.84 km). I-481 serves as an eastern bypass of Syracuse, New York. NY 481 is a northwestern extension of I-481 that ends in Oswego.[37] I-781 extends for 4.9 miles (7.9 km), that connects Fort Drum, New York, to the Interstate.[38] NY 281 is a north–south state highway in Central New York in the US that extends for 16.56 miles (26.65 km) across Cortland and Onondaga counties, roughly paralleling I-81 and connecting at both ends.[39]

I-181 was a 23.85-mile (38.38 km) offshoot of I-81, linking to Kingsport, Tennessee. It was decommissioned in August 2005 when I-26 took over I-181's entire length.[40] I-281 was replaced in January 1970 by I-481. I-81E was replaced by the current I-380.[41]


  1. ^ a b "Table 1: Main Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways". FHWA Route Log and Finder List. Federal Highway Administration. December 31, 2021. Retrieved July 14, 2022.
  2. ^ "Roads". Miller's House Museum. Retrieved July 16, 2018.
  3. ^ Perrier, Dianne (2010). Interstate 81: The Great Warriors Trace. Gainesville: University Press of Florida. ISBN 978-0-8130-3481-2. OCLC 502304332.[page needed]
  4. ^ Zuckerman, Jake (January 26, 2017). "FBI forms human trafficking task force along I-81". North Virginia Daily. Retrieved June 22, 2020.
  5. ^ Rossi, Isabella (February 12, 2019). "Sex trafficking closer to home than most Virginians would think". Collegiate Times. Retrieved June 22, 2020.
  6. ^ "Corridor Coalition". Retrieved January 29, 2018.
  7. ^ "I-81 Safety Conference". Harrisburg, PA: WHP-TV. Retrieved October 4, 2014.[permanent dead link]
  8. ^ I-81 Corridor group[dead link]
  9. ^ Natzke, Stefan; Neathery, Mike & Adderly, Kevin (June 20, 2012). "What is the National Highway System?". National Highway System. Washington, DC: Federal Highway Administration. Retrieved July 1, 2012.
  10. ^ Fiske, E.B.; Logue, R. (2006). The Fiske Guide to Colleges. New York: Times Books. p. 358. ISBN 9781402203749. Retrieved February 26, 2018 – via Google Books. The university straddles Interstate 81, an outlet to several major East Coast cities.
  11. ^ Harbaugh, Charles IV; Pennington, Jeff (2015). Middletown. Images of America. Charleston, SC: Arcadia Publishing. p. 10. ISBN 978-1-4671-2242-9. Retrieved February 26, 2018 – via Google Books.
  12. ^ a b Highway Information Services Division (December 31, 2013). Highway Location Reference. Maryland State Highway Administration. Retrieved February 3, 2018.
  13. ^ a b "Previous Interstate Facts of the Day". Eisenhower Interstate Highway System Home Page. See June 8, 2010. Archived from the original on April 26, 2006. Retrieved February 3, 2018.
  14. ^ Google (February 3, 2018). "Overview Map of I-81 in New York" (Map). Google Maps. Google. Retrieved February 3, 2018.
  15. ^ Rice, Otis K.; Brown, Stephen W. (1993). West Virginia: A History. Lexington: University Press of Kentucky. p. 10. ISBN 978-0-8131-1854-3. Retrieved February 2, 2018.
  16. ^ White, M. Wood (1873). "Counties of Morgan, Berkeley, Jefferson" (Map). White's Topographical, County & District Atlas of West Virginia. 1:310,000. M.W. White. p. 22. OCLC 62726043. Retrieved February 2, 2018 – via David Rumsey Map Collection.
  17. ^ "New York's Main Highways Designated by Numbers". The New York Times. December 21, 1924. p. XX9.
  18. ^ "Penn-Can Road Vital to Broome, Majority at Hearing Says" (PDF). The Binghamton Press. January 9, 1957. p. 3. Archived from the original (PDF) on January 30, 2022. Retrieved February 3, 2018 – via Fulton County Historical Society.
  19. ^ American Association of State Highway Officials (August 14, 1957). Official Route Numbering for the National System of Interstate and Defense Highways (Map). Scale not given. Washington, DC: American Association of State Highway Officials – via Wikimedia Commons.
  20. ^ a b "Interstate 81: The History". New York State Department of Transportation. ((cite web)): Missing or empty |url= (help)[full citation needed]
  21. ^ Bonnell, Robert O.; Bennett, Edgar T.; McMullen, John J. (December 15, 1958). Report of the State Roads Commission of Maryland (1957–1958 ed.). Baltimore: Maryland State Roads Commission. p. 82. Retrieved November 15, 2010.
  22. ^ Maryland State Roads Commission (1958). Maryland: Official Highway Map (PDF) (Map). Baltimore: Maryland State Roads Commission.[full citation needed]
  23. ^ Maryland State Roads Commission (1959). Maryland: Official Highway Map (PDF) (Map). Baltimore: Maryland State Roads Commission.[full citation needed]
  24. ^ "Bids Opened on Parts of Interstate 81". Charleston Daily Mail. July 29, 1958.[page needed]
  25. ^ a b "I-81 History". Virginia Department of Transportation. Archived from the original on November 13, 2007. Retrieved January 29, 2018.
  26. ^ "Interstate Hwy 81 Opens Soon". Morgantown Dominion News. October 6, 1966.[page needed]
  27. ^ Federal Highway Administration (2012). "NBI Structure Number: 100000210078011". National Bridge Inventory. Federal Highway Administration.
  28. ^ "Where Do We Stand On The Interstate?". Kingsport Times-News. May 2, 1965.[page needed]
  29. ^ "East Tennessee's Christmas Present". Kingsport Times. December 10, 1974.[page needed]
  30. ^ "Final Links of Interstate 81 to Be Opened with Friday Rites". Syracuse Post Standard. October 14, 1968.[page needed]
  31. ^ "Interstate Highway Construction". Somerset Daily News. October 22, 1968.[page needed]
  32. ^ "Interstate 81 Four-Lane Opens". Kingsport News. August 28, 1975.[page needed]
  33. ^ Johnston, Louis; Williamson, Samuel H. (2023). "What Was the U.S. GDP Then?". MeasuringWorth. Retrieved November 30, 2023. United States Gross Domestic Product deflator figures follow the MeasuringWorth series.
  34. ^ Rand McNally (2014). The Road Atlas (Walmart ed.). Chicago: Rand McNally. pp. 46, 71, 87–89, 95, 106–107, 112. ISBN 978-0-528-00771-2.
  35. ^ Virginia Department of Transportation. "Virginia Interstate Exits". Virginia Department of Transportation. Retrieved February 3, 2018.
  36. ^ Virginia Department of Transportation (2013). "2012 Virginia Department of Transportation Daily Traffic Volume Estimates Including Vehicle Classification Estimates" (PDF). Virginia Department of Transportation.
  37. ^ State of New York Department of Transportation (January 1, 1970). Official Description of Touring Routes in New York State (PDF) (Map). Albany: New York State Department of Transportation. Retrieved February 3, 2018.[full citation needed]
  38. ^ "Fort Drum connector road officially open". Syracuse, NY: YNN Central New York. December 6, 2012. Archived from the original on February 10, 2013. Retrieved February 2, 2018.
  39. ^ Highway Data Services Bureau. "2014 Traffic Volume Report for New York State" (PDF). Albany: New York State Department of Transportation. Retrieved February 2, 2018.
  40. ^ Allen, Calvin (July 16, 2003). "The Political History of I-26". Mountain Xpress. Asheville, NC. Retrieved February 2, 2018.
  41. ^ American Association of State Highway Officials (June 27, 1958). Official Route Numbering for the National System of Interstate and Defense Highways as Adopted by the American Association of State Highway Officials (Map). Scale not given. Washington, DC: American Association of State Highway Officials. Retrieved February 7, 2018 – via Wikimedia Commons.
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