SC 19 operates as arterial four-lane highway from Aiken to the Savannah River Site; to its north, it is a two-lane rural highway to Trenton, where it connects with US 25 and SC 121. In Aiken's downtown area, SC 19 is signed, northbound along Chesterfield Street and Richland Avenue ; while SC 19 southbound travels along Laurens Street/Park Avenue onto Chesterfield Street.
History
SC 19 is an original state highway, established in 1922. Its original routing was from SC 2 in Newberry, north through Whitmire, Union, Spartanburg, Inman and Landrum, to the North Carolina state line continuing as NC 19. In 1923, it was extended south on new primary routing, through Saluda, to SC 21/SC 27 in Trenton. In 1927, US 176 was assigned to SC 19 from Newberry to the North Carolina state line; the following year it was removed from the overlap. Also in 1928, SC 19 was extended south, replacing part of SC 27 to US 1/US 78 in Aiken. In 1929 or 1930, SC 19 was extended south to SC 28 north of Ellenton. Around 1952, the Savannah River Site was established; which removed of highway in what is now a restricted area. By 1955, SC 19 was widened to four-lanes between the Savannah River Site and Aiken. In 1964, SC 19 was truncated to its current northern terminus at Trenton; its routing north to Saluda was replaced by SC 121.
South Carolina Highway 19 Truck provides routing west around downtown Aiken, via SC 118, for trucks; which are not allowed in the downtown area.
Aiken connector
South Carolina Highway 19 Connector is a short hidden connector route, which is signed as northbound SC 19, between Park Avenue and Richland Avenue. Northbound SC 19 continue northbound along Richland Avenue to reconnect southbound SC 19 at Laurens Avenue.
Trenton connector
South Carolina Highway 19 Connector is a unsigned connector route through Trenton, via Samuel E. Diggs Road and Wise Street. Sharing a concurrency with SC 121 Conn, it has appeared on official state maps since the 1930s. The routing provides a primary routing through the center of Trenton.