Interstate 26 in South Carolina

Interstate 26 (I-26) is a South Carolina Interstate highway running generally east–west from near Landrum, in Spartanburg County, to U.S. Route 17 (US 17), in Charleston, South Carolina. It is also the longest Interstate Highway in South Carolina.

Route description
I-26 runs 221 mi through South Carolina. Milemarkers run from west (north) to east (south). Milemarker 0 is in the mountains at the North Carolina state line. The last exit, at US 17 south of Charleston, is exit 221.

I-26 runs between the Broad and Saluda Rivers, descending from the mountains to the piedmont or midlands. At Columbia, I-126 crosses the confluence of the Broad and Saluda, which together form the Congaree, near the Columbia Canal and water treatment plant. I-26 continues following the Congaree until it hops south over into the Cooper and Ashley Drainage, then down to the coast.

I-26 is predominantly a four-lane rural Interstate with 70 mph speed limits. In the Columbia and Charleston areas, the Interstate widens to six lanes, but speeds are lower.

I-26 enters South Carolina just northeast of Landrum, traveling a southeasterly direction. The first major city along its route is Spartanburg, where it intersects I-85 to Greenville and Charlotte. As the Interstate weaves along the terrain, it reaches Clinton; where westbound travelers can connect with I-385 toward Greenville. Traveling through the Sumter National Forest, it connects with Newberry before entering the Midlands. At Columbia in a section known as "Malfunction Junction", it connects with I-20 to Augusta and Florence and I-126 toward the downtown area; it then goes south over the Saluda River and into Lexington County for the second of eventually four times along its course. At Cayce, it connects with I-77 to Charlotte. South of Cayce, the Interstate goes up and down a few very long hills before reaching the outskirts of Orangeburg and I-95 to Savannah and Florence. As it enters the relatively flat plains of the Lowcountry, the area becomes urbanized as the Interstate encroaches upon North Charleston and Charleston. As the Interstate curves through the peninsula formed by the Ashley and Cooper rivers, it connects with I-526 to Savannah and Mount Pleasant. Near the end, it overlaps with US 17 from its new interchange (from the Arthur Ravenel Jr. Bridge) to where the old interchange remnants and where I-26 ends (formally where the John P. Grace Memorial Bridge and Silas N. Pearman Bridge connected).

Services
The South Carolina Department of Transportation (SCDOT) operates and maintains one welcome center and seven rest areas along I-26. Welcome centers, which have a travel information facility on site, are located at milemarker 3 (eastbound); rest areas are located at milemarkers 63 (east and westbound), 123 (east and westbound), 150 (eastbound), 152 (westbound), and 204 (eastbound). Common at all locations are public restrooms, public telephones, vending machines, picnic area, and barbecue grills.

The South Carolina Department of Public Safety (SCDPS) and State Transport Police (STP) operates and maintains three truck inspection/weigh stations. A westbound weigh station can be found at milemarker 93.5 in Chapin 17 mi west of Columbia, and two others at milemarker 173 (eastbound) and milemarker 174 (westbound) in Harleyville east of the interchanges with I-95 and US 15.

History
Construction of I-26 began in 1957 in the Columbia area with the 9 mi section from the Broad River to near Irmo. The 11 mi section of I-26 from I-126/US 76 in Columbia to US 176 at exit 97 was the first section of the highway to open up to traffic (on September 7, 1960). The 6 mi section from South Carolina Highway 210 (SC 210) to US 15 opened in September 1962. Construction proceeded in stages heading both west up toward Greenville and east toward Charleston. The highway was largely completed from Columbia to North Charleston by 1964; the section from Aviation Avenue to the highway's terminus at US 17 in downtown Charleston progressed more slowly due to land takings for the right-of-way and numerous bridges and viaducts that had to be built. The entire 221 mi of I-26 were completed by February 1969.

In the 1980s–1990s, I-26 around Columbia was widened from four to six lanes. In the mid-1990s, the North Charleston area was also widened from four to six lanes, part of which was further widened to eight lanes in the early 2010s. In 2005, the US 17 was realigned to a new interchange with I-26 at exit 220 from exit 221; the old interchange was mostly torn down and reconfigured, leaving the I-26 viaduct eastbound offramp and westbound onramps with US 17 south. In the mid-2010s, I-26 was widened southeast of Columbia from I-77 to Old Sandy Run Road. Starting in 2019 or 2020, a long stretch of I-26 northwest of Columbia will begin widening construction from four to six lanes from SC 202 at Little Mountain to US 76/US 176 at Irmo.

In 2011, a plan to add a lane in each direction between Broad River Road and Saint Andrews Road through "Malfunction Junction" had $8.5 million (equivalent to $ million in ) in funding but was expected to start sometime after 2012 and take two years.

On October 5, 2016, I-26 had all lanes converted to westbound only, from I-77 to I-526, due to Hurricane Matthew. This was done again on September 11, 2018, due to Hurricane Florence, and in September 2019 for Hurricane Dorian.

On November 19, 2016, construction began in Charleston to demolish, reconfigure, and replace exits 217 and 218, related to a new access road to the Hugh K. Leatherman Sr. Terminal; the interchange was opened on February 23, 2021.

On October 18, 2018, SCDOT approved widening I-26 between Columbia and Charleston. SCDOT plans to widen I-26 from Old Sandy Run Road in Calhoun County to Ridgeville Road (SC 27) in Berkeley County. Work on the road widening project officially began in October 2022.

On July 6, 2023, a tractor trailer pulling an excavator hit a bridge carrying Bachman Chapel Road over I-26 in Newberry when it was too tall to clear it. The bridge was deemed to be so damaged that it was closed indefinitely. The driver of the truck did not stop.

Future
SCDOT is currently working on several projects to improve I-26 along its entire route in South Carolina. In Columbia, work has begun on the "Carolina Crossroads" project to redo improve the Interstate corridors in the city. These improvements are being made increase mobility and enhance traffic operations by reducing existing traffic congestion within the I-20/I-26/I-126 corridor, while accommodating future traffic needs. The corridor's approximately 16 mi of mainline Interstate include I-26 from exit 101 (Broad River Road/US 176) to east of the Saluda River, I-20 from the west of the Saluda River to west of the Broad River, and I-126 from I-26 to east of the interchange with Colonial Life Boulevard. A $62.1 million project to convert the US 21 interchange south of Columbia from a partial cloverleaf interchange to a diamond interchange started in May 2023 and is expected to be completed in 2026. Another project to redo exit 91 will be fully opened on July 12, 2023. Long-term plans call for much of I-26 to be widened from four to six lanes between Columbia and Charleston. The project is expected to cost $2 billion and will also include rebuilding bridges and reconfiguring interchanges, including I-95 interchange near Holly Hill. Bidding for at least a part of the 70 mi project is expected to begin by the end of 2023 with construction tentatively scheduled to start in the middle of 2024.

Auxiliary routes
I-26 in South Carolina has two extant and one former auxiliary route. I-126 in Columbia and I-526 in Charleston are spur routes in their respective cities. I-326 was an unsigned designation that was decommissioned and is now part of I-77 in Columbia.