in
Washington, Pennsylvania 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, what was later built as
I-90. The Southwestern Extension, authorized in 1955, was to run south from the main line near
Pittsburgh to
West Virginia, where it connects with an extension of the
West Virginia Turnpike. Except for the section between Washington and
Greater Pittsburgh, which was included as part of
I-70, the first portion of I-79 to be added to the plans was north from Pittsburgh to Erie, along the
US 19 corridor. In September 1955, two short urban portions were designated: • 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
I-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
I-77 at
Beckley, West Virginia, 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 section bypassed part of
West Virginia Route 73 (WV 73) between
Bridgeport and
Fairmont. Another opened in July 1968, extending the highway on a bypass of downtown Fairmont to exit 137 (East Park Avenue). It was further extended toward
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 , 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 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 stretch was opened, from exit 105 (Jane Lew) south to exit 99 (
Weston). In 1973, significant portions of the Interstate were completed. A 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. On October 16, 1974, two pieces of I-79 were opened: the other two lanes of the from exit 155 to the state line and 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
US 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 I-77 in 1979. 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 1984, the route was extended about further to the north, with the opening of a new segment between
US 20 and
PA 5 in Erie. I-79 was completely rebuilt from the West Virginia state line to Erie from 1991 to 1993. Pavement was rebuilt bridge decks replaced, and rest area rebuilt. Milepost based exit numbers were introduced to the Pennsylvania portion in 2001. 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. During 2010, PennDOT undertook a $20.8 million improvement of I-79, Neville Island Bridge as well as other intersections. On December 22, 2010, WVDOT competed construction on a new interchange to serve Route 173. In 2010, construction began on improvements to exit 88. This was competed in December 2012. Construction began in 2011 on improvements to the interchange with Interstate 70 in South Strabane. They were competed in Summer 2013. This involved construction of a new underpass. In 2025, WVDOT expects to compete a six-lane widening between Harrison County and the Pennsylvania state line. ==Exit list==