Interstate 526

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Interstate 526 marker

Interstate 526
Mark Clark Expressway
I-526 highlighted in red
Route information
Auxiliary route of I-26
Maintained by SCDOT
Length19.56 mi[1] (31.48 km)
Major junctions
West end US 17 / SC 7 in Charleston
  I-26 in North Charleston
US 52 / US 78 in North Charleston
East end US 17 / I-526 Bus. in Mount Pleasant
CountiesCharleston, Berkeley
Highway system
SC 522SC 527

Interstate 526 (I-526) is a 19.56-mile (31.48 km) spur route of Interstate 26, which provides a de facto by-pass of US 17 north around Charleston, South Carolina in the United States.

Route description[edit]

I-526 begins at an incomplete interchange with US 17 (Savannah Highway) and SC 7 (Sam Rittenberg Boulevard) in the West Ashley section of the city of Charleston, just north of the Stono River. The interchange includes a loop ramp from northbound US 17, a ramp from southbound US 17, and a half-diamond interchange with SC 7. The four-lane freeway heads north past the Citadel Mall and meets SC 461 at a partial cloverleaf interchange. SC 461 heads west as Glenn McConnell Parkway and east as Paul Cantrell Boulevard; both directions lead to SC 61 (Ashley River Road). I-526 crosses SC 61 and uses the General William C. Westmoreland Bridge to cross the Ashley River into the city of North Charleston. The freeway has diamond interchanges with Leeds Avenue and SC 642 (Dorchester Road) and crosses over CSX's Charleston Subdivision.[2]

I-526 continues through a connected pair of half-diamond interchanges with Montague Avenue and International Boulevard. Both streets lead to the North Charleston Coliseum and Charles Towne Square; the latter one is the access road for Charleston International Airport. The Interstate curves east and reaches its junction with I-26, which is a cloverleaf interchange except for a flyover ramp from eastbound I-526 to westbound I-26. I-526 crosses over Norfolk Southern Railway's SC Line and has a partial cloverleaf interchange with Rivers Avenue, which carries US 52 and US 78. The Interstate continues from its overpass of the U.S. Highways as a viaduct above wetlands along Filbin Creek. The viaduct crosses over the CSX rail line again and has a four-ramp partial cloverleaf interchange with Rhett Avenue and a half-diamond interchange with Virginia Avenue. The Rhett Avenue interchange includes a U-turn ramp that allows access from westbound I-526 to Virginia Avenue and from the avenue to eastbound I-526.[2]

I-526 crosses the Cooper River on the high-level Don N. Holt Bridge and enters the Daniel Island section of the city of Charleston in Berkeley County. The freeway has partial cloverleaf interchanges with on either side of Beresford Creek with Clements Ferry Road and the pair of Seven Farms Drive and River Landing Drive. Both interchanges lead to Blackbaud Stadium, home of the Charleston Battery, and the Family Circle Tennis Center, home of the Family Circle Cup. I-526 continues southeast across the Wando River on the James B. Edwards Bridge back into Charleston County and the town of Mount Pleasant. The freeway has a partial cloverleaf interchange with Long Point Road and curves south at Hobcaw Creek. I-526 has a partial flyover interchange to and from US 17 in the direction of Georgetown before the Interstate reaches its eastern terminus at partial cloverleaf interchange with US 17 (Johnnie Dodds Boulevard). The highway continues as the I-526 Business, a four-lane highway that follows Chuck Dawley Boulevard to SC 703 in the center of Mount Pleasant.[2]

All of I-526 is included as part of the National Highway System, a system of roadways important to the nation's economy, defense, and mobility.[3]


Planning of the freeway dates back to the 1960s; construction on the first section began in 1979. Opened in 1982 as an unnumbered freeway, it traversed from Ashley River Road (SC 61) to Leeds Avenue, crossing over the Ashley River.

In 1985, the freeway became SC 31, connecting US 17/SC 7 to Dorchester Road (SC 642). By 1987 it extended to International Boulevard, providing access to the Charleston International Airport.[4]

In 1989, the freeway was rechristened as Interstate 526, after it connected with Interstate 26 (exit 212). In 1992, I-526 was extended east over the Cooper River, to Daniel Island, then over the Wando River, to Mount Pleasant and its current eastern terminus with US 17 and I-526 Business.[5]

In 1993, the Robert B. Scarborough Bridge was opened, connecting downtown Charleston with James Island; it is signed as SC 30. Since 1993, several residents and groups in the area have fought against the completion of I-526, which will connect both James Island and Johns Island.[6][7] Approximately 10 miles (16 km) separate the eastern terminus of I-526's current extent from the eastern terminus of SC 30. The mileage markers and exit numbers on both SC 30 and I-526 are based on an eventual merging of the routes, with miles 1 to 3 occurring on SC 30 and miles 10 to 30 used on the current I-526 route.


The proposed missing section of Interstate 526 was the subject of an environmental study that was completed in early 2014.[8] Various alternative routings and options are being reviewed; but the general plan is to extend south from US 17 to Johns Island and then east to James Island, where it will connect with SC 30 (possibly renumbering it). Some alternatives shown include the possibility that it will be built in expressway grade instead, falling short of being labeled an Interstate highway.[9]

Citing Charleston County's inability to provide funds to cover the project's increased cost, the State Transportation Infrastructure Bank (SIB) board voted on May 26, 2016, to abandon the proposed extension of I-526 across James and Johns Islands.[10]

Exit list[edit]

CharlestonCharleston10.0016.0910 US 17 (Savannah Highway) / SC 7 (Sam Rittenburg Boulevard) – SavannahWestern terminus
11.3918.3311 SC 461 (Paul Cantrell Boulevard / Glenn McConnell Parkway) to SC 61 (Ashley River Road)Split into exits 11A (south) and 11B (north)
Ashley RiverGeneral William C. Westmoreland Bridge
North Charleston13.9122.3914Leeds Avenue
14.7423.7215 SC 642 (Dorchester Road) / Paramount Drive
15.5825.0716 Montague Avenue / International Boulevard – Charleston International AirportSplit into exits 16A (Montague Avenue and International Boulevard) and 16B (Airport) eastbound
17.0427.4217 I-26 – Charleston, ColumbiaSplit into exits 17A (east) and 17B (west) westbound
17.6528.4018 US 52 / US 78 (Rivers Avenue)Split into exits 18A (east) and 18B (west)
19.0930.7219North Rhett AvenueIncludes direct U-turn ramp from westbound I-526 exit to eastbound I-526 entrance
19.3931.2120Virginia AvenueEastbound exit, westbound entrance; movements between Virginia Avenue and I-526 to and from Mount Pleasant are made using the exit 19 U-turn ramp
Cooper RiverDon N. Holt Bridge
BerkeleyCharleston22.5036.2123Clements Ferry RoadSplit into exits 23A (south) and 23B (north) eastbound
23.9638.5624River Landing Drive / Seven Farms Drive / Island Park Drive – Daniel Island
Wando RiverJames B. Edwards Bridge
CharlestonMount Pleasant27.4644.1928Long Point Road
28.6946.1729 US 17 north – GeorgetownEastbound exit, westbound entrance
29.5647.5730 US 17 (Johnnie Dodds Boulevard) / I-526 Bus. (Chuck Dawley Boulevard) to SC 703 – CharlestonEastern terminus; roadway continues as I-526 Spur; no access from eastbound I-526 to northbound US 17 or from southbound US 17 to westbound I-526
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

Interstate 526 Business[edit]

Interstate 526 Business
LocationMount Pleasant, South Carolina
Length1.60 mi[11] (2.57 km)

Interstate 526 Business (I-526 Bus.) is a 1.6-mile (2.6 km) four-lane boulevard-grade business spur of I-526 along Chuck Dawley Boulevard, between Johnnie Dodds Boulevard (US 17) and Ben Sawyer Boulevard (SC 703). The route was originally part of US 17 Bus./US 701 Bus.; signed east-west, it has not changed since inception.

I-526 Bus. is not part of the National Highway System.[3]

The entire route is in Mount Pleasant, Charleston County.

0.00.0 I-526 west / US 17 – North Charleston, Charleston, GeorgetownWestern terminus; continuation as I-526
1.62.6 SC 703 – Charleston, Sullivan's IslandEastern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

See also[edit]


  1. ^ a b Highways - Zipped Shapefile of roads maintained by SCDOT - Statewide (ESRI shapefile) (Map). South Carolina Department of Transportation. 2012. Retrieved May 31, 2012.
  2. ^ a b c Google (May 21, 2013). "Interstate 526" (Map). Google Maps. Google. Retrieved May 21, 2013.
  3. ^ a b "National Highway System: Charleston--North Charleston, SC" (PDF). United States Department of Transportation. October 1, 2012. Retrieved August 14, 2013.
  4. ^ General Highway Map, Charleston County, South Carolina (PDF) (Map). Cartography by SCDOT. South Carolina Department of Transportation. 1987. Retrieved May 20, 2013.
  5. ^ General Highway Map, Charleston County, South Carolina (PDF) (Map). Cartography by SCDOT. South Carolina Department of Transportation. 1996. Retrieved May 20, 2013.
  6. ^ "I-526 Extension". Coastal Conservation League. July 28, 2010. Retrieved September 19, 2011.
  7. ^ "So Much to Lose For So Little Gain". Nix 526. Retrieved September 19, 2011.
  8. ^ "SCDOT - I-526 - Welcome to the Mark Clark Expressway!". SCDOT. September 30, 2010. Retrieved May 20, 2013.
  9. ^ Staff. "RPA Overview" (PDF) (Map). Mark Clark Expressway Environmental Impact Study. South Carolina Department of Transportation. Retrieved May 20, 2013.
  10. ^ "S.C. agency moves to walk away from Charleston's I-526 extension".
  11. ^ Google (May 19, 2013). "Overview map of I-526 Bus." (Map). Google Maps. Google. Retrieved May 19, 2013.

External links[edit]

Route map:

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