I-77 highlighted in red
|Length||613.41 mi (987.19 km)|
|South end||in Cayce, SC|
| near Columbia, SC|
in Charlotte, NC
in Statesville, NC
near Mt. Airy, NC
between Fort Chiswell and Wytheville, VA
between Beckley and Charleston, WV
near Charleston, WV
in Cambridge, OH
in Akron, OH
/ in Richfield, OH
|North end||in Cleveland, OH|
|States||South Carolina, North Carolina, Virginia, West Virginia, Ohio|
Interstate 77 (I-77) is a north-south Interstate Highway in the eastern United States. It traverses diverse terrain, from the mountainous state of West Virginia to the rolling farmlands of North Carolina and Ohio. It largely supplants the old U.S. Route 21 between Cleveland, Ohio, and Columbia, South Carolina, as an important north–south corridor through the middle Appalachians. The southern terminus of Interstate 77 is in Columbia at the junction with Interstate 26. The northern terminus is in Cleveland at the junction with Interstate 90. Other major cities that I-77 connects to include Charlotte; Charleston, West Virginia and Akron, Ohio. The East River Mountain Tunnel, connecting Virginia and West Virginia, is one of only two instances in the United States where a mountain road tunnel crosses a state line. The other is the Cumberland Gap Tunnel, connecting Tennessee and Kentucky. I-77 is a route to the southern United States for those traveling from the Great Lakes region.
I-77 begins as an eight-lane highway at I-26 in the far southeastern part of the Columbia metropolitan area. In the Columbia area, I-77 offers access to Fort Jackson before meeting I-20 in the northeastern part of the city. This segment of I-77, combined with I-20 and I-26, form a beltway around Columbia, though it is not officially designated as such.
After leaving the northern Columbia suburb of Blythewood, I-77 narrows to four lanes until it widens to eight lanes at Rock Hill from Exit 77 to the North Carolina state line at I-485.
The final section of the entire length of Interstate 77 was completed in Columbia in 1995.
Interstate 77 through North Carolina begins at the South Carolina state line at Pineville. It narrows to 6 lanes on the NC side south of Charlotte and then widens to 8 and 10 lanes through downtown before entering the North Carolina Piedmont region. In Charlotte it intersects Interstate 85 as well as intersecting each of the loops of Interstate 485 and Interstate 277 (twice). North of Charlotte, it skirts Lake Norman where it narrows again to 4 lanes before passing through Huntersville, Cornelius, Davidson and Mooresville. Forty miles north of Interstate 85, at Statesville it intersects Interstate 40 and U.S. Highway 70. Next, it crosses over U.S. Route 421 in Yadkin County and continues on through Elkin. The final intersection in the state is with a discontinuous section of Interstate 74 near Mount Airy.
Interstate 77 in Charlotte, North Carolina, is also known as the "Bill Lee Freeway"; this designation stretches from Exit 6 (South Tryon Street/Woodlawn Road) in Charlotte to Exit 33 (US 21 North), near Mooresville. A 6-mile (9.6-km) portion south of the city is called the "General Younts Expressway". When I-77 crosses over I-85 (which runs in an east–west direction through the interchange), the northbound lanes are to the west of the southbound lanes.
North Carolina completed its section of Interstate 77 in 1975.
Interstate 77 through Virginia passes through two tunnels, The Big Walker Mountain Tunnel and the East River Mountain Tunnel. For eight miles (13 km), Interstates 77 and 81 overlap near Wytheville. This is a wrong-way concurrency, where two roads run concurrent with each other but are designated in opposite directions.
On March 31, 2013, there was a nearly 100-car pileup on I-77 near Fancy Gap; as a result of that crash, electronic variable speed limit signs are now in place along that stretch of I-77. The speed limit can be adjusted according to driving conditions at a given time.
Interstate 77 enters West Virginia through the East River Mountain Tunnel. At milepost 9, Interstate 77 becomes co-signed with the West Virginia Turnpike for the next 88 miles (142 km), a toll road between Princeton and Charleston. It is concurrent with Interstate 64 to Charleston at Beckley. The speed limit is 70 mph (110 km/h) for most of the length, with a 60 mph (97 km/h) limit for the section between Marmet and the toll plaza near Pax.
It enters Charleston via the Yeager Bridge before splitting off at a four-level junction with Interstate 64. Two miles north of the city center, it junctions with Interstate 79 before proceeding northward towards Ripley and Parkersburg.
North of Charleston, Interstate 77 is known as the "Korean War Veterans Memorial Highway".
The interchange with I-70 at Cambridge is (or at least at one time was) thought to be the largest interchange in the world, covering over 300 acres (1.2 km2) of land.
Other major Interstate Highways I-77 connects with in Ohio are I-76, I-80 (Ohio Turnpike), and I-90. The interchange with the Ohio Turnpike was completed on December 3, 2001, providing direct access; previously, traffic had to exit at Ohio State Route 21 to get to the Turnpike.
Officially designated to run from Port Huron, Michigan to Charlotte, I-77 appeared on the original Interstate system route numbering plan in 1957. The part of Interstate 94 from Detroit northeast to Port Huron, Michigan, was originally planned as I-77 in 1957; the current I-77 was I-79. When the current Interstate 79 was added in Pennsylvania, the I-77 designation was moved to its current route, but the I-77 in Michigan also remained in the 1958 numbering plan. It soon became part of I-94.
Originally, I-77 was to terminate at Interstate 85 in Charlotte. However, Congress, in its 1969 amendments to the Interstate Highway Act, added an extension of I-77 from I-85, through a rapidly growing corridor from downtown Charlotte (along an upgrading of US 21 already under construction in some places), into South Carolina near Rock Hill. The highway under this plan was to continue to Columbia, South Carolina, terminating at an interchange with Interstate 26. Collector / distributor ramps to both Alpine and Percival Roads were proposed later on to more efficiently route traffic to and from the Fort Jackson military reservation and the I-77 / I-20 corridors.
By the late 1970s, the southern terminus of I-77 near Columbia, South Carolina, was amended to a grade-separated interchange with SC 12 (Percival Road) with mile markers signed accordingly. This extension was completed in 1986. That same year, the first phase of an interstate spur (to be named Interstate 326) between SC 760 (Jackson Boulevard) and Interstate 26 was opened as far as Bluff Road (SC-48). 1989 saw a two-mile (3 km) extension to the east, adding interchanges at Shop Road (later SC-768) and Garner's Ferry Road / Sumter Highway (US 76/US 378).
The decision to extend I-77 from SC 12 and SC 760 (five miles between the two roads) was made before I-326 was opened, so the southern portion was never signed as such, instead re-designated by SC DOT as SC-478. The northern part of extension was completed as far as Forest Drive in early 1993, with the final 3 miles (4.8 km), including the SC-760 interchange, opened to traffic in 1995. The mile markers and exit numbers for Interstate 77 were adjusted accordingly as the extension was completed. As the Percival Road to I-26 section was under construction, southbound traffic on I-77 was detoured, by "Temporary I-77" signage, via I-20 and I-26 to bypass Columbia.