US 52 ALT #1: Appeared Feb 1937 (SCDOT) as new BELT routing, running from US 52 southeast into Lake City to Church St (now US 378 Bus), then west on SC 341 Main St back to US 52.
By 1940, US 52 ALT was rerouted to leave Main St south along Acline St to US 52 south of Lake City.
In 1953, US 52 ALT was downgraded S-21-10; US 378; S-21-32.
US 52 ALT #2: Appeared about 1939 as new primary routing, running from US 52-78 Rivers Ave southeast on Carver Ave and Meeting St to end at US 17-701 Lee St in Charleston.
By 1942, US 52 ALT was extended north along Meeting St. to end at US 52-78/SC 531 (Rivers at Durant).
It appears by 1945, US 52 ALT below Spruill Ave may have become part of SC 525.
In 1947, Meeting St became S-10-39 north of Rivers Ave and mainline US 52 south of it.

US 52 ALT in Lake City 1940 Florence County

US 52 ALT in Charleston 1940 Charleston County

US 52 ALT #3: Appeared about 1940 as new primary routing, running from US 52-301/SC 51 to SC 518 (now S-21-13 National Cemetery Rd).
In 1947, US 52 ALT was downgraded to S-21-12. US 52 ALT used James Jones Ave and Church St.
US 52 ALT #4: Appeared about 1953 as new primary routing, running from US 52 Meeting St along Morrison Dr and E. Bay St to end at Broad St in downtown Charleston.
In 1968, US 52 ALT was decommissioned. Today this is now US 52 SPUR.

US 52 ALT in Florence 1940 Florence County

Another US 52 ALT in Charleston 1960 Charleston County