of the National Highway System, a system of routes determined to be the most important for the nation's economy, mobility, and defense. History US 123 replaced all of SC 13 in 1946. SC 13 was SC 17 before 1928. South Carolina Highway 13 SC 13's Greenville alternate route South Carolina Highway 13 Alternate (SC 13 Alt.) was an alternate route for the original SC 13 (that was replaced by US 123). It existed in Greenville, South Carolina. It was formed around 1940 from SC 250 (now US 25) to SC 13. Approximately 1950, SC 13 Alt. was decommissioned, and US 123 replaced its path. Major intersections Special routes Seneca business loop U.S. Route 123 Business (US 123 Bus) was established in 1958 as a renumbering of mainline US 123 through downtown Seneca, via North 1st Street. It was decommissioned in 2000, renumbered as part of SC 59 and SC 130. Easley business loop U.S. Route 123 Business (US 123 Bus) was established in 1958 as a renumbering of mainline US 123 through downtown Easley, via Liberty Drive and Main Street. It was decommissioned in 1963 when mainline US 123 was rerouted further south along new freeway; the alignment was renumbered as part of SC 93. Easley connector route U.S. Route 123 Connector (US 123 Conn.) is a connector route in the west-central part of Easley that connects SC 93 (Greenville Highway / Liberty Drive) with US 123 (Calhoun Memorial Highway). The connector route is not signed along SC 93 or US 123, but there is signage along its actual path. The entire length is known as Ross Avenue. US 123 Conn. and Ross Avenue begin at an intersection with SC 93 mainline and travel to the east. Immediately, they curve to the southeast. They curve back to the east just before reaching their eastern terminus, an intersection with US 123. Greenville alternate route See also References External links The Highways of South Carolina: US 123 Endpoints of U.S. Highway 123 23-1 1 23-1 23-1 Transportation in Habersham County, Georgia Transportation in Stephens County, Georgia Transportation in Oconee County, South Carolina Transportation in Pickens County, South Carolina Transportation in Greenville County, South Carolina