Interstate 81

Interstate 81 Virginia
Interstate 81 West Virginia
Interstate 81 Maryland
Interstate 81 Pennsylvania
I-81 New York


Following the spine of the Appalachian Mountains, Interstate 81 provides a major trucking corridor and link from the Southeastern States and Tennessee Valley northward to the Northeastern Megalopolis. Interstate 81 does not enter major metropolitan areas; it instead serves an array of small to mid-size cities.

The route commences from a rural directional T interchange near Dandridge, Tennessee to run northeast across agricultural areas and forest land along the west side of the Appalachian Mountains to the Tri-Cities region. A spur route, I-181, once connected I-81 with Kingsport and Johnson City. It was renumbered in 2003 as a northern extension of Interstate 26 from Asheville, North Carolina.

Crossing into Virginia by the two-state city of Bristol, Interstate 81 combines with U.S. 58 to Abingdon. A short spur, I-381, links I-81 with the Bristol city center as the freeway bypasses the community to the north. Further east, I-81 combines with Interstate 77 along a “wrong-way” overlap, where I-77 south combines with I-81 north and vice versa due to their east-west orientation between Wytheville and Fort Chiswell.

I-77 leads north to Charleston, West Virginia and south to Charlotte, adding truck traffic from the Carolinas to Interstate 81 as it progresses northeast to Christiansburg, Roanoke and Lexington. I-581 represents the second urban spur for Interstate 81, as it combines with U.S. 220 south through Roanoke while the parent freeway stays north by Salem.

Interstate 64 combines with I-81 from Lexington northeast to Staunton as part of the route between Beckley, West Virginia and Roanoke, Virginia. Additional truck traffic funnels onto I-81 south from central Virginia via I-64. Northward from I-64, I-81 continues to Harrisonburg, Strasburg and the west end of I-66, and Winchester to exit the state through the Eastern Panhandle West Virginia.

The short stretch through the Mountaineer State takes I-81 through the urban area of Martinsburg. The section concludes at the Potomac River and Williamsport, Maryland. The freeway stays urban along the west side of Hagerstown between the crossroads with I-70 and Hagerstown Regional Airport (HGR). Truck traffic remains heavy as the route enters the Keystone State nearby.

Angling northeast, Interstate 81 and nearby U.S. 11 pass through Chambersburg and Carlisle en route to the Harrisburg area. U.S. 11 provides the connection to Interstate 76 (Pennsylvania Turnpike) in lieu of direct access as I-81 turns more easterly toward the capital city. U.S. 11 eventually turns north along the Susquehanna River, leaving the freeway to follow U.S. 22 to Interstate 78 and an independent route northeast to Hazelton and Wilkes-Barre.

U.S. 11 rejoins the I-81 corridor at Wilkes-Barre, following at-grade routes northeast to Scranton while I-81 hugs the east side of the urban area to I-84/380 and the freeway spur taking U.S. 6 to Carbondale. West from there, I-81 passes between urban Scranton and Dickson City and briefly combines with U.S. 11 to the north end of Interstate 476 (Pennsylvania Turnpike – Northeast Extension).

The remainder of Interstate 81 generally travels north along side U.S. 11 between Scranton and the Thousand Islands Bridge into Canada. An urban stretch takes I-81 through the city of Binghamton, where NY 17/I-86 overlap to the Prospect Mountain Construction Project. The long term rebuild of I-81/86 between NY 7 and their split over the west banks of the Chenango River was completed on December 1, 2019.12 I-86 follows the Southern Tier of New York west to Elmira and Corning while I-81 joins Binghamton with Cortland and Syracuse.

Through Syracuse, I-81 passes through the city center while Interstate 481 provides a suburban bypass to the east. The I-81 Viaduct Project study evaluated options for addressing the aging viaduct around Downtown. The Preferred Alternative is the Community Grid, which replaces a portion of I-81 with an at-grade boulevard and relocates I-81 over I-481. With the release of the Final Environmental Statement, ground breaking is scheduled for Fall 2022.

Beyond Syracuse, I-81 travels along a mostly rural course east of Lake Ontario to Watertown, where Interstate 781 spurs east to Fort Drum. The northern extent of I-81 ties into the Thousand Islands Bridge system spanning the St. Lawrence Seaway to the freeway along Ontario Highway 401 in Canada.

Parallel U.S. Routes

U.S. 11 parallels freeways for the majority of route from New Orleans north to Watertown, New York. I-81 runs along the US highway from east of Bristol, Virginia to Upstate New York, with the exception of between Harrisburg and Wilkes-Barre, Pennsylvania. Through Tennessee, U.S. 11 partitions into the branches of 11E and 11W, along the Interstate 81 corridor between Knoxville and Bristol. U.S. 22 also parallels the freeway from Harrisburg northeast to I-78 near Jonestown, Pennsylvania.

Interstate 81 through Syracuse

Constructed in the 1950s and 60s, the 1.4 mile long elevated viaduct of Interstate 81 through Syracuse is deteriorating and in need of replacement. The substandard design also does not meet current Interstate standards. An environmental review process was initiated by the New York State Department of Transportation (NYSDOT) and Federal Highway Administration (FHWA). Preliminary engineering commenced in 2015 to evaluate various alternatives proposed for addressing future transportation needs along Interstate 81 and for the city of Syracuse.

Those considered include a major overhaul of the Syracuse freeway network, where I-81 would be relocated along Interstate 481 and the through-route of I-81 be severed and replaced by state-maintained urban boulevard to the south and a freeway spur from the north. Associated work of the estimated $1.9 billion, Community Grid plan would redesign the north and south ends of I-81 to provide two through lanes in each direction with 65 MPH design speeds. Other alternatives included replacing the elevated route of I-81 through Syracuse with a modern viaduct at the cost of $2.2 billion. Open houses and a series of public meetings preceded the selection of the preferred alternative by NYSDOT8.

State officials selected the Community Grid option in April 2019. Additional public meetings followed and comments on the Draft Environmental Impact Statement (DEIS) for the Community Grid were taken by the FHWA and NYSDOT until September 14, 2021. The Final Environmental Impact Statement was published on April 15, 2022, allowing for the planned ground breaking to take place in Fall 2022.

The American Association of State Highway Officials (AASHO) approved conditionally both the elimination of I-81 through the city of Syracuse and the realignment of I-81 in place of I-481 at the Spring 2021 Meeting. Business Loop I-81 was also approved in place of the existing I-81 between south Syracuse and the town of Cicero.


Tennessee’s portion was completed by 1975.4 Further north in Virginia, Interstate 81 opened between November 1959 and July 1987. The first portion of any Interstate highway opened in West Virginia was the segment of I-81 through Berkeley County in 1961.7 The Maryland portion of Interstate 81 first opened in 1962 between U.S. 40 and the Maryland state line. Completion of the southern segment within the Free State followed by the mid 1960s.3

Interstate 81 within Pennsylvania opened in segments between 1960 and 1976.2 Within New York, Interstate 81 was established in 1957, with construction completing the route between 1967 and 1969.5

A branch route of Interstate 81 was designated from Scranton southeast to Pocono Township in northeastern Pennsylvania. Initially proposed as part of Interstate 82 by Pennsylvania on August 14, 1957, the route was renumbered by the American Association of State Highway Officials (AASHO) on June 27, 1958 as Interstate 81S.6 This later was renumbered again to I-81E and ultimately to Interstate 380 as confirmed by AASHO on June 20, 1972.

1965 map inset of Syracuse, New York.
Syracuse, NY in 1965

A 4.1 mile section of I-81 in the city of Syracuse, New York opened to traffic north from U.S. 11 (Exit 16) at Neadrow to Exit 17 (Calthrop Avenue) in December 1965. Completion of this segment allowed motorists to save six to eight minutes of travel time over parallel U.S. 11 along Salina Street. Construction finished a year and 45 days ahead of schedule. By late December 1965, Interstate 81 was extended another a 22.7 miles south to Polkville (Exit 10).10

The final portion of Interstate 81 in New York built was the 4.96 mile segment crossing Wellesley Island. Opened over a year ahead of schedule, barricades were removed along the new section without fanfare at 11 AM on November 18, 1970. The four lane freeway linked the Thousand Island Bridge with the International Rift Bridge.11

The north end of Interstate 81 ties into the Alexandria Bay Port of Entry on Wellesley Island. The port of entry dates back to 1938, when the Thousand Islands International Bridge System was built. The Main Administration Building and Passenger Processing Facility was constructed by the Thousand Islands Bridge Authority in 1975. A $215 million modernization and expansion project got underway at the crossing on August 30, 2017. Improving efficiency and upgrading outdated infrastructure, the two phase project relocated the port nearly 300 yards south of the previous and added to the number of inspection lanes. A ribbon cutting event was held by U.S. Customs and Border Protection (CBP) on July 21, 2022.13

Route Information

  • North End – Alexandria Bay, NY

  • South End – Dandridge, TN

  • Branch Routes – 4

  • Total Mileage – 855.02


Tennessee – 75.66

  • Cities – Morristown, Kingsport, Johnson City, Bristol

  • JunctionsI-40 I-26

Virginia – 324.92*

  • Cities – Bristol, Marion, Wytheville, Christiansburg, Roanoke, Lexington, Staunton, Harrisonburg, Winchester

  • JunctionsI-381 I-77 I-581 I-64

West Virginia – 26.00

  • Cities – Martinsburg

  • Junctions – none

Maryland – 12.08

  • Cities – Hagerstown

  • JunctionsI-70

Pennsylvania – 232.76

  • Cities – Chambersburg, Shippensburg, Carlisle, Harrisburg, Frackville, Mahanoy City, Hazelton, Wilkes-Barre, Scranton

  • JunctionsI-76 PA Turnpike I-83 I-78 I-80 I-476 I-84 I-380

New York – 183.60

  • Cities – Binghamton, Cortland, Syracuse, Watertown

  • JunctionsI-86 I-88 I-481 I-690 I-90 NY Thruway I-781

Source: December 31, 2021 Interstate Route Log and Finders List
* – 30.40 miles on I-64, 8.80 miles on I-77

I-81 Annual Average Daily Traffic (AADT)

Eastern Tennessee - 1970
Northeastern Tennessee – 1970 Tennessee Official Highway Map

The southernmost 12 miles of Interstate 81 and the short stretch leading into Virginia were open to traffic by 1970. Per the 1973 Tennessee Official State Map, all of I-81 was under construction, with the route open northward to U.S. 11E near Mohawk Crossroad and southward to SSR 126 at Blountville.

Eastern Pennsylvania - 1965
Interstate 81 between the I-78 and I-80 corridors – 1965 Pennsylvania Official Highway Map

Construction was underway from Exit 145 northward to the Butler Drive overpass along I-81 in 1965. The stretch would open between PA 93 (former PA 29) north to I-80 in 1967.2

Northern New York - 1963
Interstate 81 corridor through Upstate New York – 1963

Segments of I-81 open by 1963 included the portion from Park Street and Onondaga Lake Parkway (NY 370) in Syracuse to NY 342 (former NY 181) north of Watertown and a bypass of U.S. 11 to the west of La Fayette. Additionally the Thousand Islands Bridge, dedicated on August 18, 1938, was incorporated as the I-81 connection to Ontario, Canada.

Tolling Interstate 81 in Virginia

Discussed by the state of Virginia in December 2003 was the idea of how to best expand Interstate 81 throughout the Commonwealth. Several proposals emerged due to the state’s Public-Private Transportation Act. Of these, two concepts were considered the front runners:

  • Star Solutions Proposal. Expand Interstate 81 to eight overall lanes with a separation between car and truck lanes. This major overhaul was estimated to cost upwards of $10.9 billion and to be funded with truck tolls, which were legalized on trucks by the Virginia General Assembly in 2001.
  • Fluor Virginia Proposal. Expand Interstate 81 to six lanes, with the implementation of car and truck tolls. Notably, car tolls were not legally permitted on existing Interstate highways in Virginia at the time. This concept entailed a $7 billion price tag.

The major concern with the first option was that creator of the plan to expand the freeway to eight lanes, Star Solutions, included a request for a “noncompete” clause in its contract. That meant that VDOT was disallowed from undertaking any new projects that would increase the capacity or overall improve any highways within the I-81 corridor for the 40-year life of the Interstate 81 bonds. This red tape would have impacted U.S. 11, U.S. 29 and Interstate 95 among other north-south routes in the state.

Under the Fluor Virginia concept, issues arose with the concept of tolling cars. While tolls were legal for trucks, they remained prohibited on automobile traffic, requiring an amendment by the General Assembly for the Fluor Virginia plan to go forward.1

With either option, construction was not expected to begin until at least 2007. However subsequent developments led to the cancellation of all proposals related to tolling Interstate 81.

North End – Canadian International Border – Alexandria Bay, New York

I-81 North

I-81 north at NY 12 - Alexandria, NY

Interstate 81 meets NY 12 at a cloverleaf interchange (Exit 50) between the town of Orleans and Alexandria, just ahead of the 1,000 Islands Bridge. Photo by Doug Kerr (09/10/11).

I-81 north at 1000 Islands Br - Orleans, NY

I-81 reduces to two lanes across the tolled 1,000 Islands Bridge spanning the St. Lawrence River onto Wellesley Island. Photo by Doug Kerr (09/10/11).

I-81 north at Island Rd - Wellesley Island, NY

I-81 north reaches the last U.S. exit for Island Road (CR 191) and De Wolf Point just south of the Canadian port of entry. 03/24/23

I-81 north at Island Rd - Wellesley Island, NY

CR 191 connects the north end of I-81 with Wellesley Island and Dewolf Point State Parks as it leads southward along Lake of the Isles. 03/24/23

I-81 north at Island Rd - Wellesley Island, NY

The final Interstate 81 confirming marker stands within the exchange at Island Road, a short distance from the twin 90 foot arch bridges over the international rift boundary to Hill Island, Ontario.9 03/24/23

County Route 191 at I-81

CR 191 north at I-81 - Alexandria, NY

CR 191 turns west at Travis Road into the exchange at the north end of Interstate 81. 03/24/23

CR 191 north at I-81 - Alexandria, NY

The northbound entrance ramp for I-81 was realigned as part of the 2017-22 Alexandria Bay Port of Entry expansion project underway.13 03/24/23

CR 191 north at I-81 - Orleans, NY

Crossing into the town of Orleans, CR 191 passes under I-81 ahead of the southbound entrance ramp to Watertown. 03/24/23

CR 191 north at I-81 - Orleans, NY

Paralleling CR 191, Interstate 81 encircles Lake of the Isles southward on Wellesley Island toward the Thousand Islands Bridge. 03/24/23

CR 191 south at I-81 - Alexandria, NY

CR 191 east links Deringer Drive and facilities at the Alexandria Bay Port of Entry with the north end of Interstate 81. 03/24/23

I-81 South

I-81 south at Island Rd - Wellesley Island, NY

The first confirming marker for Interstate 81 south stands just beyond the port of entry at the diamond interchange with Island Road (CR 191). Photo by Douglas Kerr (09/10/11).

I-81 south at Island Rd - Wellesley Island, NY

Interstate 81 expands to four lanes across Wellesley Island to a folded diamond interchange (Exit 51) with CR 100 (Island Road). Photo by Douglas Kerr (09/10/11).

I-81 south at Island Rd - Wellesley Island, NY

Exit 51 departs I-81 south for CR 100 and parallel CR 191 (Island Road) north. Interstate 81 reduces to two lanes ahead of the Thousand Islands Bridge crossing the St. Lawrence River. Photo by Douglas Kerr (08/26/12).

I-81 Thousand Islands Bridge

The Thousand Islands International Bridge System travels 8.5 miles overall from Ivy Lea, Ontario to Collins Landing, New York.9 Tolls are collected in the southbound direction on the Canadian side of the border. Photo by Douglas Kerr (08/26/12).

I-81 Thousand Islands Bridge

The 4,500 foot long span over the American channel of the St. Lawrence River crests at a height of 150 feet. Ground breaking for the two lane suspension bridge took place on August 30, 1937. The span was completed ten weeks ahead of schedule in August 19389 Photo by Douglas Kerr (08/26/12).

East at

Highway 401 east at Highway 137 - Leeds Grenville, ON

Approaching Highway 137 (Exit 661) south on Highway 401 (Macdonald-Cartier Freeway) east near the community of Selton. Interstate 81 spans the Raft Narrows (St. Lawrence River) along a combination of a 750-foot long suspension bridge from the mainland south to Georgina Island, and a 600-foot Warren Truss span between Constance and Hill Islands.9 Photo by Jeff Morrison (06/27/07).

Highway 401 east at Highway 137 - Leeds Grenville, ON

An Interstate 81 trailblazer precedes the trumpet interchange (Exit 601) with Highway 137 south to Hill Island on Highway 401 east. Highway 137 comprises a four-lane freeway south to Thousand Islands Parkway. Photo by Jeff Morrison (06/27/07).

I-81 North End Throwback

Ontario Highway 401 east at Highway 137 - 2002

Replaced sign bridge for Highway 401 (Macdonald-Cartier Freeway) east at Highway 137 south (Exit 661). Highway 401 constitutes a 515 mile long limited access route between Windsor, near Detroit, Michigan, and Quebec near Cornwall, Ontario. Photo by Douglas Kerr (11/08/02).

Ontario Highway 401 west at Highway 137 - 2002

Entering the township of Leeds and the Thousand Islands, motorists along Highway 401 (Macdonald-Cartier Freeway) west passed by the initial guide sign for Exit 661 and Highway 137. Removed by 2009, a supplemental sign was added in its place referencing the Thousand Islands Bridge system to I-81 south. Photo by Douglas Kerr (11/08/02).

Ontario Highway 401 west at Highway 137 - 2002

A new sign bridge was posted further east for Exit 661 on Highway 401 Macdonald-Cartier Freeway by 2009. The Macdonald-Cartier Freeway continues west 30 kilometers to Kingston and 235 kilometers to Toronto. Highway 137 travels two kilometers south to the Thousand Islands toll plaza. Photo by Douglas Kerr (11/08/02).

South End I-40 – near Dandridge, Tennessee

I-81 South at I-40

I-81 south at I-40 - White Pine, TN

Interstate 81 advances south two miles to I-40 (Exits 1A/B) from a rest area near the community of Kansas. All guide signs for I-40 on I-81 south were replaced by 2013. 01/16/19

I-81 south at I-40 - White Pine, TN

Crossing Dry Branch, a diagrammatic sign follows for the directional T interchange (Exits 1A/B) with I-40. 01/16/19

I-81 south at I-40 - White Pine, TN

Two lanes default onto Exit 1B for the 30-mile drive along Interstate 40 west to Knoxville. A grade level directional ramp curves southward to merge onto the left side of Interstate 40 east ahead of Douglas Lake and Newport. 01/16/19

I-40 West at I-81

I-40 west at I-81 - Dandridge, TN

Interstate 40 crosses Douglas Lake ahead of SR 113. The freeway continues northwest two miles to meet Interstate 81. Photo by Carter Buchanan (06/10/17).

I-40 west at I-81 - Dandridge, TN

TDOT traffic counts along this stretch were recorded at 29,677 vehicles per day (vpd) in 2018. The advent of traffic from I-81 south swells the 2018 count to 71,311 vpd beyond Exit 421. Photo by Peter Johnson (03/28/21).

I-40 west at I-81 - Dandridge, TN

I-81 leads northeast to the Tri-Cities Region along a rural course to Bristol. Photo by Peter Johnson (03/28/21).

I-40 west at I-81 - Dandridge, TN

I-81 leads 80 miles northeast from Exit 421 to Bristol on the Virginia state line. Photo by Peter Johnson (03/28/21).

I-40 west at I-81 - Dandridge, TN

Interstate 40 turns west from I-81 and expands into a six lane freeway en route to Dandridge, Sevierville and Knoxville. Photo by Peter Johnson (03/28/21).

I-40 East at I-81

I-40 east at I-81 - Dandridge, TN

Late 1990s construction along I-40 widened the freeway to six lanes with a barrier median to the split with Interstate 81 north (Exit 421). Similar to I-81 south, a rest area precedes their exchange along I-40 east. 05/31/07

I-40 east at I-81 - Dandridge, TN

Interstate 40 eastbound expands to four lanes to Left Exit 421 with I-81 north. The freeway turns southward from I-81 along a winding and scenic route across the Bald and Great Smoky Mountains. 05/31/07

I-40 east at I-81 - Dandridge, TN

Passing over Koontz Creek and Valley Home Road (SR 66), Interstate 40 continues to within a half mile of Exit 421 with I-81 north. I-81 north to I-26 south provides an alternate route to North Carolina in case of emergency closures along Interstate 40 through Pigeon River Gorge due to rock slides or inclement weather. 05/31/07

I-40 east at I-81 - Dandridge, TN

Two thirds of the traffic along Interstate 40 east shifts to I-81 north toward the Tri-Cities and southwest Virginia. I-40 heads south and then east on the 80 mile drive to Asheville, North Carolina. Photo by Jeffrey Napier (01/02).

I-81 South End Throwback

I-81 South at I-40

I-81 south at I-40 - 2007

Two miles ahead of I-40 on Interstate 81 southbound. 05/31/07

I-81 south at I-40 - 2007

Replaced overhead for Interstate 40. 06/25/12

I-81 south at I-40 - 2007

The previous overhead for Exit 1B displayed just one lane for I-40 west. 06/25/12

I-40 West at I-81

I-40 west at I-81 - 1998

A diagrammatic sign replaced separate panels for I-40 and 81 on the one mile approach to the directional interchange at Exit 421 by 2007. Photo by Jim K. Georges (07/98).

I-40 East at I-81

I-40 east at I-81 - 1995

Prior to the late 1990s expansion of Interstate 40 eastbound from two to three lanes, this set of guide signs directed motorists for the upcoming split with I-81 north. 05/29/95

I-40 east at I-81 - 1995

Replaced by 1998, nondescript guide signs previously directed motorists one half mile ahead of the I-40 east and I-81 northbound split. 05/29/95

I-40 east at I-81 - 1995

Overheads at the Exit 421 separation indicated just one through lane for I-40 east to Asheville and I-81 north to Bristol. 05/29/95


  1. “VDOT Criticizes 2 Consortium’s Plans to Widen I-81.” Roanoke Times (VA), November 15, 2003.
  2. Pennsylvania Highways: Interstate 81.
  3. MDRoads: I-81.
  4. Interstate 81 in Virginia (RoadstotheFuture).
  5. Interstate 81 in New York.
  6. Interstate system route numbering web site, Stephen Summers.
  7. “Research panel predicts state road fund shortage.” Charleston Gazette (WV), June 22, 2006.
  8. “Rethinking I-81: Eastern suburbs could see new highway names, interchanges, lanes.” The Post-Standard (Syracuse, NY), November 16, 2016.
  9. 75th Anniversary Fact Sheet, Thousand Islands Bridge Authority.
  10. “Interstate 81 Ready to Please When Open. The Post-Standard (Syracuse, NY), November 23, 1965.
  11. “81 Segment Completed at Wellesley.” The Post-Standard (Syracuse, NY), November 19, 1970.
  13. “Grand Opening of Alexandria Bay Port of Entry.” U.S. Customs and Border Protection, local media release. July 21, 2022.

Page updated April 5, 2023.