Interstate 79 constitutes a two-state freeway that links Charleston, West Virginia with Pittsburgh and Erie, Pennsylvania. The freeway winds northeast from the West Virginia capital city along a mountainous route to Clarksburg, Fairmont and Morgantown, home of the University of West Virginia. Heading into the Commonwealth of Pennsylvania, I-79 swings westward toward Waynesburg and Washington for a brief overlap with Interstate 70.
North from there, I-79 bends back to the east through Canonsburg, Bridgeville, Carnegie and other west Pittsburgh suburbs. The freeway bypasses the Steel City to the Ohio River at Corapolis and the Pennsylvania Turnpike at Cranberry Township. Beyond there from Harmony north toward Lake Erie, Interstate 79 travels a rural route to meet I-80 outside Mercer and I-90 at Mc Kean Township. The freeway transitions into Bayfront Parkway to the west of Downtown Erie at the northern terminus.
Parallel U.S. Routes
Interstate 79 largely follows U.S. 19 from Sutton, West Virginia north to Erie, Pennsylvania. The westward leg between Sutton and Charleston partially lines U.S. 119 from Clendenin to I-77 at Charleston. U.S. 119 also intermingles with the I-79 corridor through Morgantown.
Interstate 79 was initially established by American Association of State Highway Officials (AASHO) on June 27, 1958 to run from Erie south to Pittsburgh in Pennsylvania.1 The route south to Charleston was added during the 1960s. Through the Pittsburgh area, I-79 was planned to loop into the Steel City along the alignment of Interstate 279 / Parkway North, while I-279 would have provided the bypass route via the current alignment of I-79 through the western suburbs. This arrangement remain proposed until at least 1968. Also in 1960 Penn-Lincoln Parkway was designated as Interstate 70. It changed to I-76 by 1964 and eventually to Interstate 376. Renumbering of the main Interstates through Pittsburgh took place after it was determined that through-traffic needs were more important.
Approved by AASHO on November 12, 1958, the northernmost segment of Interstate 79 between I-90 and the city of Erie was designated as Interstate 179.1 This changed by 1968, if not sooner. The only instance in the current Interstate system where a 2-digit route ends as a 3-digit branch of itself is in Dallas, Texas, where the north end of Interstate 45 transitions into unsigned IH 345.
Construction of Interstate 79 in Pennsylvania commenced in 1961 and finished in 1979.2
A substandard connection between Interstate 79 and the Pennsylvania Turnpike (I-76), known as the Cranberry Connector, required travelers to use PA 228 to connect between two routes. This non-freeway connection and the associated crossing of U.S. 19 nearby generated travel headaches for years. A $44.3 million project conducted by PennDOT and the Pennsylvania Turnpike Commission replaced the surface link with a direct freeway connector. Construction included the building of a new collector distributor roadway along I-79 south to PA 228 (completed late September 2003) and a new roadway from I-76 to U.S. 19 and I-79 (completed on October 15, 2003).3,4
North End – Erie, PA
South End – Charleston, WV
Branch Routes – 2
Total Mileage – 343.46
West Virginia – 160.52
Cities – Charleston, Weston, Clarksburg, Fairmont, Morgantown
- Junctions –
Pennsylvania – 182.94*
Cities – Washington, Pittsburgh, Meadville, Erie
Source: December 31, 2018 Interstate Route Log and Finders List
* – 3.55 miles on I-70
I-79 Annual Average Daily Traffic (AADT)
Source: Pennsylvania Traffic Volume Map 2017 (Penndot)
Once Interstate 70 was relocated from Pittsburgh southward onto its current alignment between Washington and New Stanton, Pennsylvania, Penn-Lincoln Parkway was redesignated as I-79 on the West portion and as the westernmost extent of I-76 on the East portion.
The Interstate 179 designation made it into the 1963 Rand McNally Road Atlas. All other editions showed the freeway leading into Erie as simply I-79.
Two sections of Interstate 79 were completed in West Virginia by 1972: from Jane Lew to Quiet Dell and from McAlpin through the Fairmont area to a point south of Uffington and Morgantown.
North End – Erie, Pennsylvania
North at / Bayfront Pkwy
North End Throwback
South End – Charleston, West Virginia
- Interstate system route numbering web site
http://www.nwindianahwys.homestead.com/INTER_MAIN.HTML, Stephen Summers.
- Pennsylvania Highways: Interstate 79.
- “PennDOT touts benefits of Cranberry Connector .” The Post-Gazette, September 6, 2003
- Kitsko, Jeff. “Remaining ramps of the Cranberry Connector Opening Right Now.” Online posting, misc.transport.road, October 15, 2003.
Page updated January 14, 2020.