Wythe County's location, at the confluence of I-81 and I-77 which is, incidentally, a wrong-way concurrency, has led to its growth for industry and tourism.

Route 309 follows the Cross Valley Expressway from the junction of I-81 and PA-115 to the West Side communities and also has an interchange with River Street in the township.

The northern terminus has short merge areas with I-81, especially the left merge in the southbound direction.

The southern section, in northern Rockingham County, has a length of from Interstate 81 ( I-81 ) and U. S. Route 11 ( US 11 ) at Mauzy through Broadway to the West Virginia state line into Mathias.

The two outlets share studios on James Street / NY 290 in Syracuse northeast of downtown and the I-690 / I-81 interchange.

The two stations share studios on James Street ( NY 290 ) in Syracuse northeast of downtown and the I-690 / I-81 interchange.

In the interchange with NY 5 to the east, two lanes of I-690 disappear, and I-81 follows directly after in the center of the city with an incomplete interchange.

NY 3 interchanges with I-81 at the city line.

Northeast of Carlisle in Middlesex, US 11 interchanges with the Pennsylvania Turnpike ( Interstate 76 ) and I-81 in succession.

Now running south, the Beltway interchanges with VA 7 ( Leesburg Pike ) east of Tysons Corner ; passing Dunn Loring to the east, I-495 soon reaches the complex interchange with Interstate 66, which extends westward to I-81 in the Shenandoah Valley near Strasburg, Virginia, and eastward to Arlington and downtown Washington.

So one might simultaneously be on I-77 north and I-81 south, while actually traveling due west.

Interstate 84, Interstate 380. and U. S. Route 6 meet I-81 at the Throop Dunmore Interchange in Dunmore near Throop.

The planned construction will also move the I-81 interchange at Stephens City, where there are a number of service stations and fast food restaurants, south of the town limits to alleviate congestion on the current Route 277 bridge, which will remain after construction is completed.

After a short concurrency with US 11 in downtown Wytheville, it goes north and ends at the intersection of I-81 / US 52.

NY 298, which connects to I-81 at exit 22 west of the I-81 / I-690 interchange, must be used to make these connections.

US 211 begins at a diamond interchange with I-81 just west of the town of New Market.

At Clinton Road, US 11 and NY 41 turn west while NY 13 curves east for several blocks to an interchange with I-81 at the northeastern edge of the city's downtown district.

The route continues along I-81 northbound until Daleville, at an interchange with US 220 Alternate.

It ends at I-81 northwest of Strasburg.

West of the city of Watertown, NY 3 intersects NY 180 southwest of the Watertown International Airport before connecting to I-81 by way of an interchange at the city line.

Just outside the hamlet, NY 104 meets I-81 at exit 34.

Past I-81, NY 104 heads east and southeast for nine miles ( 14 km ) through the predominantly rural towns of Albion and Williamstown to its eastern terminus at a junction with NY 13.

The portion of I-81 near Maple View was completed in late 1961, at which time US 104 was extended eastward over NY 126 to meet the new highway.

WV 45 intersects I-81 at a diamond interchange and continues east as Apple Harvest Drive, a four-lane undivided highway that passes through a commercial area south of the city limits of Martinsburg where the highway meets the Winchester and Western Railroad at grade and intersects US 11 ( Winchester Avenue ).

SR 259 begins at the diamond interchange between I-81 and US 11 ( Valley Pike ) at Mauzy.

The exit ramp from southbound I-81 alights at the state highway just north of its terminal intersection.

The highway ends at the U. S. border, where it continues as I-81.

* Whitney Point – The Village of Whitney Point in the southwest part of the town by I-81 and US-11.

I-81 is the third longest Interstate highway whose number does not end with a 0 or 5 after I-94 and I-64.

NY 17 splits from I-81, the Erie Railroad and the Susquehanna River to the east into Stilson Hollow ; from this split ( exit 75 ) to its end, most of NY 17 does not follow the Erie Railroad, which crosses into Pennsylvania several times.

NY 126 was truncated on its west end to the I-81 interchange as a result.

I-40 intersects with eight of the 10 primary north – south interstates ( all except I-5 and I-45 ) and also with I-24, I-30, I-44, I-77, and I-81.

New York State Route 17 is partly conjoined with I-81 in the town.

NY 17 merges here with I-81 for 5 miles before splitting in Binghamton.

The wrong-way concurrency is also reflected in U. S. Route 52 and U. S. Route 11, which are concurrent with I-77 and I-81, respectively.

Its route will be Myrtle Beach to Hamlet, North Carolina ; following I-74 to Greensboro ; north to Roanoke, Virginia ; following I-81 to Christiansburg ; via Blacksburg to I-77 to Huntingdon ; following I-74 to Piketon, Ohio ; north to Columbus and Toledo ; northwest to Jackson, Michigan ; and north to Lansing before finally joining with I-75 south of Grayling.

In between, NY 13 intersects with Interstate 81 ( I-81 ) in Cortland and Pulaski and meets the New York State Thruway ( I-90 ) in Canastota.

It is co-signed with I-581 from downtown Roanoke to I-81 north of the city.

* At the interchange of Interstate 70 and Interstate 81 in Hagerstown, Maryland, the control city for I-81 south is Roanoke, Virginia, over away, with the control cities of Martinsburg, West Virginia and Winchester, Virginia overlooked.

The state highway also connects Shepherdstown in northern Jefferson County with Martinsburg, where the highway meets Interstate 81 ( I-81 ), U. S. Route 11 ( US 11 ), and WV 9.

US Route 11 and I-81 pass near the east town line by the Tioghnioga River.

As it proceeds across the state, it intersects many of New York's Interstate and U. S. Highways, including U. S. Route 219 ( US 219 ) in Salamanca, US 15 ( future I-99 ) near Corning, I-81 in Binghamton, and I-84 near Middletown.

In Camp Hill, a close suburb of Harrisburg, US 11 stops paralleling I-81 and joins U. S. Route 15 northward through the western suburbs of Harrisburg.

Known for most of its length as Lee Highway, the U. S. Highway runs from Interstate 81 ( I-81 ) and Virginia State Route 211 ( SR 211 ) in New Market east to US 15 Business, US 29 Business, and US 211 Business in Warrenton.

Past NY 104B, Route 3 parallels both Interstate 81 ( I-81 ) and US 11 as it heads along the shore of Lake Ontario.