I-79 highlighted in red
|Length||343.24 mi  (552.39 km)|
|South end||I‑77 in Charleston, WV|
I-70 near Washington, PA
I-376 near Carnegie, PA
I-76 / Penna Turnpike in Warrendale, PA
I-80 in Findley Township, PA
I-90 in McKean, PA
|North end||PA 5 / PA 290 / Bayfront Parkway in Erie, PA|
|States||West Virginia, Pennsylvania|
PA: Greene, Washington, Allegheny, Butler, Lawrence, Mercer, Crawford, Erie
Interstate 79 (I-79) is an Interstate Highway in the eastern United States, designated from Interstate 77 in Charleston, West Virginia to Pennsylvania Route 5 and Pennsylvania Route 290 in Erie, Pennsylvania. It is a primary thoroughfare through western Pennsylvania and West Virginia, and makes up part of an important corridor to Buffalo, New York, and the border with Canada. Major metropolitan areas connected by I-79 include Charleston and Morgantown in West Virginia, and Pittsburgh, and Erie in Pennsylvania.
In West Virginia, Interstate 79 is known as the Jennings Randolph Expressway, named for Jennings Randolph. In the three most northern counties it is signed as part of the High Tech Corridor. For most of its Pennsylvania stretch, it is known as the Raymond P. Shafer Highway, named for Raymond P. Shafer.
Except at its northern end, I-79 is located on the Allegheny Plateau. Despite the somewhat rugged terrain, the road is relatively flat. Most of the highway is at an elevation of about 1,000 to 1,200 feet (300 to 370 metres) above sea level, with some lower areas near both ends and higher areas near Sutton, West Virginia. In the hillier areas, this flatness is achieved by curving around hills, along ridges, and in or partway up river valleys.  From Sutton, West Virginia north, Interstate 79 generally parallels the path of U.S. Route 19.
I-79 begins at a three-way directional Y interchange with Interstate 77 along the northwest bank of the Elk River just northeast of Charleston. For its first 67 miles (108 km), to a point just south of Flatwoods, I-79 is located in the watershed of the Elk River, which drains into the Kanawha River. It crosses the Elk River twice — at Frametown and Sutton - and never strays more than about 15 to 20 miles (24 to 32 km) from it.  
The freeway into Pittsburgh requires drivers to use I-376 while I-79 completely bypasses the city. Beyond the Pittsburgh area, I-79 traverses more rural areas in Butler, Lawrence, Mercer, Crawford, and Erie counties before arriving at its termination point in Erie. In Erie, I-90 provides an important connection from I-79 to Buffalo, New York and the border with Canada.
Around the 100 mile marker on the northbound side are two ghost ramps that were specifically built for the Boy Scouts of America in order to have access to Moraine State Park without having to get on U.S. Route 422 for the 1973 and 1977 National Scout Jamborees, which were held at Moraine. The ramps were permanently closed after the 1977 event, but remain in place as of 2017.  
I-79 was completely re-built in the Pittsburgh area in the early 1990s. 
The Pennsylvania General Assembly authorized the Pennsylvania Turnpike Commission to build two extensions in the 1950s. The Northwestern Extension, authorized in 1953, was to stretch from the main Pennsylvania Turnpike north to Erie, and would have included a lateral connection between Ohio and New York (later built as Interstate 90).  The Southwestern Extension, authorized in 1955, was to run south from the main line near Pittsburgh to West Virginia, connecting there with an extension of the West Virginia Turnpike.  Except for the section between Washington and the Pittsburgh area, which was included as part of Interstate 70,  the first portion of I-79 to be added to the plans was north from Pittsburgh to Erie, along the U.S. Route 19 corridor.
In September 1955, two short urban portions were designated: 
|Existed||November 12, 1958–1968|
|Length||13.5 mi (21.7 km)|
|Existed||September 16, 1989–|
- I-179: A spur from I-90 north to Erie, currently absorbed into I-79 
- I-279: A western bypass of Pittsburgh, connecting I-70 with I-80S (now Interstate 76); it and I-79 later swapped designations
The number 79 was assigned in 1958,  and an extension south along I-70 to Washington and beyond to Charleston was approved on October 18, 1961.  This extension also paralleled US 19 to near Sutton, where it turned westerly to reach Charleston. (The part of US 19 from Sutton south to Interstate 77 at Beckley, WV has since been four-laned as Corridor L of the Appalachian Development Highway System.)
On December 21, 1967, the first section of I-79 in West Virginia, between Exits 125 (Saltwell Road) and 132 (South Fairmont), opened to traffic.  This five-mile (8 km) section bypassed part of WV 73 between Bridgeport and Fairmont. Another five miles (8.0 km) opened in July 1968, extending the highway on a bypass of downtown Fairmont to Exit 137 (East Park Avenue).  It was further extended 9.5 miles (15.3 km) towards Morgantown on October 15, 1970, bypassing more of WV 73 to Exit 146 (Goshen Road) south of that city.   
On June 29, 1970 the swap of I-79 and I-279 was approved. At the same time, I-76 was extended west from downtown Pittsburgh over former I-79 to the new location of I-79 west of Pittsburgh, so I-279 only ran north from downtown Pittsburgh. On December 3, 1971, I-76 was rerouted to bypass Pittsburgh, and I-279 was extended to I-79 utilizing the former section of I-76.  The changes took effect on October 2, 1972. 
On June 29, 1973, I-79 was extended from West Virginia Exit 146 to Exit 148 ( I-68), where at one point, traffic was forced onto the newly opened west end of Corridor E (now I-68) to Exit 1.  A further extension of six miles (9.7 km), including the Uffington Bridge over the Monongahela River southwest of Morgantown, was opened on August 30, 1973, leading north to Exit 155 ( Star City).   This completed I-79 from north of Bridgeport to north of Morgantown.
To the south of Bridgeport, the first two sections were both opened on December 22, 1971. One of these ran ten miles (16 km) from Exit 51 ( Frametown) to Exit 62 ( Sutton), and the other from Exit 105 ( Jane Lew) to Exit 115 ( Nutter Fort).     On September 19, 1973, another 7.5-mile (12.1 km) stretch was opened, from Exit 105 ( Jane Lew) south to Exit 99 ( Weston). 
In 1973, significant portions of the interstate were completed.  Interstate 79 opened from Exit 62 to Exit 99. Another 23.9 miles (38.5 km), from Exit 67 ( Flatwoods) north to Exit 91 ( Roanoke), opened on November 28, 1973, along with the section from exit 115 north to exit 117 ( Anmoore), completing the route between Frametown and Morgantown except in the Bridgeport area.  
A 5.5-mile (8.9 km) extension from exit 51 south to exit 46 ( Servia) opened on February 1, 1974,  and County Route 11 to WV 4 near Duck was widened to handle the increased load.  On the same day, two lanes opened from exit 155 ( Osage) north to the state line.[ citation needed]
On October 16, 1974, two pieces of I-79 were opened: the other two lanes[ citation needed] of the 6.6 miles (10.6 km) from exit 155 to the state line, and 7.1 miles (11.4 km) between exits 117 ( Anmoore) and 125 (north of Bridgeport). On the same day, the eastern end of Corridor D and the western end of Corridor E, both connecting to I-79 (at exits 119 and 148), were opened. This completed I-79 in West Virginia north of exit 46 ( Servia);    it was extended south to exit 25 ( Amma) in late November  and to U.S. Route 119 north of Clendenin (exit 19) on November 13, 1975.  It was opened from exit 19 to exit 9 ( Elkview) on November 18, 1977,  and finally completed to Interstate 77 in 1979. 
On July 25, 1975, Interstate 79 was opened between exits 1 and 14 in Pennsylvania.  The last piece of I-79 between West Virginia and Erie — the Neville Island Bridge over the Ohio River - opened on September 3, 1976. 
In late 2008, the "missing ramps" of the I-79/I-376 interchange (PA 60 was designated as the route for southbound traffic seeking to go to Pittsburgh International Airport & airport traffic seeking to go northbound on I-79) were completed. 
In June 2009, I-376 was extended west and north of downtown Pittsburgh, and I-279 was truncated back to the section only running from downtown Pittsburgh north to I-79.
This section contains a table that is missing mileposts for one or more junctions.
|State||County||Location||mi ||km||Old exit|
|West Virginia||Kanawha||Charleston||0.000||0.000||—||I‑77 to I‑64 – Parkersburg, Charleston||Southern terminus of I-79; I-77 exit 104|
|1.845||2.969||1||US 119 – Mink Shoals||Access to Coonskin Park|
|5.047||8.122||5||US 119 (WV 114) – Big Chimney||Northern terminus of WV 114|
|Pinch||9.469||15.239||9||CR 43 (Frame Road) – Elkview|
|Clendenin||19.091||30.724||19||US 119 (CR 53) – Clendenin|
|Roane||Amma||25||CR 29 – Amma|
|||34||WV 36 – Wallback, Clay|
|Clay||||39.899||64.211||40||WV 16 – Big Otter|
|Braxton||||46||CR 11 (Servia Road)|
|Frametown||51.569||82.992||51||WV 4 – Frametown|
|||57.607||92.709||57||US 19 south – Beckley, Summersville||Southern terminus of US 19 concurrency; access to New River Gorge|
|Sutton||61.465||98.918||62||WV 4 – Sutton, Gassaway|
|Flatwoods||67||US 19 north ( WV 4) / WV 15 – Flatwoods||Northern terminus of US 19 concurrency; WV 15 ends at WV 4 south of the interchange; access to Sutton Lake|
|Burnsville||78.909||126.992||79||WV 5 – Burnsville, Glenville||Access to Glenville State College and Burnsville Dam|
||No major junctions|
|Lewis||||90.988||146.431||91||US 19 – Stonewall Resort, Roanoke||Access to Stonewall Jackson Lake State Park|
|Weston||96||CR 30 – South Weston||Access to Stonewall Jackson Lake and Jackson's Mill|
|98.608||158.694||99||US 33 / US 48 / US 119 – Weston, Buckhannon||Access to West Virginia Wesleyan College and Davis and Elkins College|
|Jane Lew||105||CR 7 – Jane Lew||Access to Jackson's Mill|
|Harrison||Lost Creek||110||WV 270 – Lost Creek||Eastern terminus of WV 270|
|Stonewood||115.75||186.28||115||WV 20 – Stonewood, Nutter Fort||Access to Alderson Broaddus University|
|Clarksburg||117||WV 58 – Anmoore|
|119||US 50 ( Corridor D) – Clarksburg, Bridgeport||Access to Salem International University|
|121||CR 24 (Meadowbrook Road)|
|||124||WV 279 to US 50 east||Access to North Central West Virginia Airport, Tygart Lake State Park, and United Hospital Center|
|||125||WV 131 (Saltwell Road) – Shinnston|
|Marion||Whitehall||132.086||212.572||132||US 250 – Fairmont, Whitehall|
|Fairmont||133||CR 64⁄1 (Kingmont Road)|
|135||CR 64 (Pleasant Valley Road)|
|136||WV 273 – Downtown Fairmont||Southern terminus of WV 273; exit fully opened on December 22, 2010. |
|136.660||219.933||137||WV 310 (East Park Avenue)||Access to Valley Falls State Park|
|139||CR 33 (Pricketts Creek Road) – East Fairmont||Access to Prickett's Fort State Park|
|Monongalia||||146||CR 77 (Goshen Road)|
|Morgantown||148.766||239.416||148||I‑68 east – Cumberland||Western terminus of I-68; access to Mountaineer Field and Tygart Lake State Park|
|||152.502||245.428||152||US 19 – Westover, Morgantown||Access to Granville|
|||153.4||246.9||153||CR 46⁄7 (University Town Centre Drive)|
|||154.836||249.184||155||WV 7 – West Virginia University||Access to Star City, Osage, and Mountaineer Field|
|Pennsylvania||Greene||Perry Township||1||1||To US 19 – Mount Morris|
|Whiteley Township||2||7||Kirby, Garards Fort|
|Franklin Township||13.971||22.484||3||14||PA 21 – Masontown, Waynesburg||Access to Waynesburg University|
|Washington Township||19.4||31.2||4||19||US 19 / PA 221 – Ruff Creek, Jefferson|
|Washington||West Bethlehem Township||23.4||37.7||5||23||Marianna, Prosperity|
|Amwell Township||30.6||49.2||6||30||US 19 – Amity, Lone Pine|
|32.9||52.9||7||33||US 40 – Laboratory|
|South Strabane Township||34.4||55.4||—||34||I-70 east – New Stanton||Southern terminus of I-70 concurrency, east exit 18|
|35.4||57.0||8||20||PA 136 (Beau Street)||Access to Washington & Jefferson College|
|36.4||58.6||7||19||US 19 (Murtland Avenue)||Diverging diamond interchange|
|37.9||61.0||—||38||I-70 west – Wheeling, WV||Northern terminus of I-70 concurrency, west exit 21|
|41.1||66.1||8||41||Race Track Road – Meadow Lands|
|North Strabane Township||43.4||69.8||9||43||PA 519 – Eighty Four, Houston|
|45.5||73.2||10||45||To PA 980 – Canonsburg|
|Cecil Township||48.2||77.6||10A||48||Southpointe, Hendersonville||Access to California University of Pennsylvania's Southpointe Campus and to the National Cemetery of the Alleghenies|
|50.2||80.8||—||52||PA Turnpike 576 (Southern Beltway)||Under contract; westbound entrances & eastbound exits are expected to open by 2019. |
|Allegheny||Bridgeville||54.6||87.9||11||54||PA 50 – Bridgeville|
|South Fayette Township||55.2||88.8||12||55||Heidelberg, Collier||Formerly designated as "Heidelberg / Kirwan Heights"|
|Pennsbury Village||59.3||95.4||14||59||I-376 ( US 22, US 30) – Pittsburgh, Pittsburgh International Airport||I-376 exit 64A; signed as exits 59A (east) & 59B (west)|
|Robinson Township||60.4||97.2||16||60||PA 60 – Crafton, Moon Run, Pittsburgh International Airport||Signed as exit 60A northbound and exits 60A (south) and 60B (north) southbound|
|Coraopolis||64.1||103.2||17||64||PA 51 – Coraopolis, McKees Rocks||No southbound exit|
|Ohio River||Neville Island Bridge|
|Neville Township||64.8||104.3||18||65||Yellow Belt to PA 51 – Neville Island||Southern terminus of Yellow Belt concurrency|
|Ohio River||Neville Island Bridge|
|Glenfield||66.5||107.0||19||66||PA 65 – Emsworth, Sewickley|
|Sewickley Hills||68.0||109.4||20||68||Yellow Belt (Mount Nebo Road)||Northern terminus of Yellow Belt concurrency|
|Franklin Park||72.1||116.0||21||72||I-279 south – Pittsburgh||Northern terminus of I-279, southbound exit and northbound entrance|
|73.3||118.0||22||73||PA 910 east / Orange Belt – Wexford||Western terminus of PA 910|
|Marshall Township||75.7||121.8||23||75||Red Belt to US 19 south – Warrendale||Northbound exit and southbound entrance|
|75.9||122.1||25||76||US 19 north – Cranberry||Northbound left exit and southbound entrance|
|Butler||Cranberry Township||77.2||124.2||—||77||I-76 / Penna Turnpike – Harrisburg, Youngstown OH||I-76 / Penna Turnpike exit 28 (Cranberry)|
|78.7||126.7||25||78||PA 228 – Seven Fields, Mars, Cranberry|
|Jackson Township||83.1||133.7||26||83||PA 528 – Evans City||Northbound exit and southbound entrance|
|85.5||137.6||26||85||To PA 528 ( US 19)||Southbound exit and northbound entrance|
|87.3||140.5||27||87||PA 68 – Zelienople||Northbound exit and southbound entrance|
|88.7||142.7||27||88||To US 19 to PA 68 – Zelienople||Signed as Little Creek Road northbound; promoted as access to Seneca Valley School District|
|Muddy Creek Township||95.8||154.2||28||96||PA 488 – Portersville, Prospect|
|Muddy Creek Township||99.6||160.3||29||99||US 422 – New Castle, Butler||Access to Moraine State Park and McConnells Mill State Park|
|Worth Township||105.4||169.6||30||105||PA 108 – Slippery Rock||Access to Slippery Rock University of Pennsylvania|
||No major junctions|
|Mercer||Springfield Township||113.7||183.0||31||113||PA 208 / PA 258 – Grove City||Access to Grove City College and Westminster College|
|Findley Township||116.5||187.5||—||116||I-80 – Clarion, Sharon||Signed as exits 116A (east) and 116B (west); I-80 exits 19A-B|
|Jackson Township||121.1||194.9||33||121||US 62 – Mercer, Franklin|
|New Vernon Township||130.6||210.2||34||130||PA 358 – Greenville, Sandy Lake||Access to Thiel College|
|Crawford||Greenwood Township||141.5||227.7||35||141||PA 285 – Geneva, Cochranton|
|Vernon Township||147.4||237.2||36||147||US 6 / US 19 / US 322 – Meadville, Conneaut Lake||Signed as exits 147A (north/east) and 147B (south/west); access to Conneaut Lake Park and Allegheny College, to PA 102|
|Hayfield Township||153.9||247.7||37||154||PA 198 – Conneautville, Saegertown|
|Erie||Washington Township||166.5||268.0||38||166||US 6N – Albion, Edinboro||Access to Edinboro University of Pennsylvania|
|178.6||287.4||—||178||I-90 – Buffalo, Cleveland||Signed as exits 178A (east) and 178B (west); I-90 exits 22A-B; former southern terminus of I-179|
|Millcreek Township||180.5||290.5||41||180||To US 19 – Kearsarge||Access to Millcreek Mall and PA 99|
|Erie||182.7||294.0||43||182||US 20 (26th Street)||Access to Erie International Airport|
|183.6||295.5||44||183||PA 5 / PA 290 east (12th Street)||Northbound exit and southbound entrance; signed as exits 183A (east) and 183B (west); access to Presque Isle State Park, Waldameer Park, and Gannon University; western terminus of PA 290|
|Northern terminus of I-79; roadway continues beyond Lincoln Avenue as Bayfront Parkway; former northern terminus of I-179|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- Interstate 279 heads southeast from Interstate 79 in Pittsburgh's northern suburbs to Interstate 376 in downtown Pittsburgh.
- Interstate 579 heads south from Interstate 279 in Pittsburgh's North Side to the Liberty Bridge and the Boulevard of the Allies just east of downtown Pittsburgh.
- "Route Log and Finder List - Interstate System - table 1". Federal Highway Administration. 2002-10-31. Retrieved 2007-07-09.
- United States Geological Survey topographic maps and aerial photos, accessed via Terraserver-USA
- National Atlas of the United States, Hydrologic Units (Watersheds) GIS data Archived 2013-05-04 at the Wayback Machine.
- "Ghost Ramps". Gribblenation.com. 2005-06-05. Retrieved 2017-08-08.
- Google (2017-08-08). "Ghost ramps around the 100 mile marker" (Map). Google Maps. Google. Retrieved 2017-08-08.
- "The Pittsburgh Press - Google News Archive Search". google.com.
- Pennsylvania Turnpike Northwestern Extension Act, P.L. 706, No. 229, passed July 28, 1953
- Pennsylvania Turnpike Southwestern Extension Act, P.L. 174, No. 52, passed June 14, 1955
- Official Route Numbering for the National System of Interstate and Defense Highways, as adopted by the American Association of State Highway Officials, August 14, 1957
- Bureau of Public Roads, General Location of National System of Interstate Highways, 1955: maps of Erie and Pittsburgh
- "3-digit Interstates from I-79". kurumi.com.
- Official Route Numbering for the National System of Interstate and Defense Highways, as adopted by the American Association of State Highway Officials, June 27, 1958
- Charleston Daily Mail, Third Route Alters Interstate Picture, SRC Tells Mayors, October 20, 1961
- Charleston Daily Mail, 5-Mile I-79 Link Will Open December 21, December 7, 1967
- Charleston Daily Mail, 5 Miles of I-79 Opens in Marion, July 20, 1968
- Charleston Gazette, Gov. Moore Will Open I-79 Segment, October 10, 1970
- Charleston Gazette, Moore Opens I-79 Portion, Restates Vow, October 16, 1970
- Release Date Report. West Virginia Department of Transportation. August 2003.
- Federal Highway Administration, Ask the Rambler: Was I-76 Numbered to Honor Philadelphia for Independence Day, 1776?
- "Interstates Renumbered". The Pittsburgh Press. February 24, 1972. p. 8. Retrieved November 30, 2017 – via Newspapers.com.
- Charleston Daily Mail, 5 More Miles of I-79 Being Opened Today, June 29, 1973
- Charleston Gazette, 6-Mile Stretch of I-79 Open, August 31, 1973
- Charleston Gazette, September 5, 1973
- Dominion News, Two I-79 Sections Opened, December 23, 1971
- Charleston Daily Mail, 40 Miles More of I-79 Open, December 23, 1971
- Charleston Gazette, I-79 Mileage Increased to 40, December 23, 1971
- Dominion News, January 23, 1972
- Charleston Daily Mail, I-79 Segment Opened by Governor Moore, September 20, 1973
- Charleston Daily Mail, More of I-79 to Be Opened Tomorrow, November 27, 1973
- Charleston Gazette, Open I-79 Increasing by 25.17 Miles, November 28, 1973
- Charleston Gazette, Additional Interstates to Open, January 30, 1974
- Charleston Gazette, Highway Project Bids to Be Opened, March 8, 1972
- Charleston Gazette, Moore Will Open 22 New Miles, October 8, 1974
- Charleston Gazette, 22 Miles of Roads Opened, October 17, 1974
- Daily Courier, W. Va. to Open Over 22 Miles of Highways, October 10, 1974
- Charleston Gazette, Holiday Travelers to Find I-79 Nonstop From Amma, November 28, 1974
- Charleston Gazette, New I-79 Stretch Will Open Today, November 13, 1975
- Charleston Daily Mail, November 18, 1977
- Daily Courier, I-79 Opening Today in Greene County, July 25, 1975
- Valley Independent, Interstate 79 opened in Erie on September 4, 1976
- "'Missing links' take shape at I-79/Parkway West". Pittsburgh Post-Gazette.
- Federal Highway Administration, National Highway Planning Network GIS data version 2005.08
- "Pennsylvania Exit Numbering" (PDF). Pennsylvania Department of Transportation. Retrieved October 2, 2007.
- Panuska, Mallory (December 22, 2010). "Gateway Connector opens today". Times West Virginian. Retrieved December 22, 2010.
- Construction on Southern Beltway set for spring Beaver County Times (01/14/2013)