Interstate 326 was the temporary designation for the southernmost section of I-77 between I-26 at Cayce and South Carolina Highway 48 (Bluff Road) at Columbia. An unsigned route, guide signs along I-326 instead referenced the freeway as “To S.C. 48” and then “TEMP S.C. 478.”1
The Federal Highway Administration (FHWA) approved a 4.95 mile long spur along the Southeastern Beltway on December 19, 1975 under authorization of 23 U.S.C. 103(e)(1). The number 326 was tentatively assigned subject to concurrence of the American Association of State Highway and Transportation Officials (AASHTO). AASHTO concurred with the South Carolina State Highway Department request for the establishment of Interstate 326 on July 13, 1976.