SC 760 into central Fort Jackson 1939 Official

SC 12 Columbia through Ft Jackson 1941 Gen Draft

Adjustments: In 1947, SC 12 was truncated to US 1 leaving behind a bit of US 1 plus Taylor St.
Also in 1947, SC 12 east was truncated to SC 760 Jackson Blvd/Forest Rd/Dixie Rd jct, leaving behind S-40-22 out to SC 760's original 1939 end point below Lake Barstow and S-40-25 the rest of the way to SC 26. Note that SC 12 did NOT use Artillery Rd/Johnson Rifle Rd but instead a mostly unpaved road directly to Messers Pond then used Messers Pond Rd and Colonels Creek Rd. SC 12 then followed Century Division Rd, Statue of Liberty Rd, and Red Diamond Rd which no longer connects to S-40-25 Shady Grove Rd.

SC 12's non-direct routing in eastern Fort Jackson and Messers Pond, downgraded to S-40-22 and S-40-25.
1948 Richland County

Although only shown on county maps, SC 12 east was truncated to the Fort Jackson boundary between 1949-51.
In late 1952, SC 12 east was rerouted to avoid Fort Jackson entirely and instead along Percival Rd replacing S-40-150 and an unknown Kershaw County designation to US 601 near Lugoff. The old road into Ft Jackson is Old Forest Rd; I-77 cuts off some of this; Forest Rd (Strom Thurmond Blvd was not part of SC 12 ever).

SC 12 truncated to Ft Jackson gate 1951 Richland County

SC 12 extended to US 601 1952 Official

In 1958, SC 12 was re-extended west over Taylor St to end at SC 555.
In 1959, SC 12 was extended west on Taylor St to end at US 76 Bull St.
In 1977, SC 12 was extended west on Taylor St then as new construction to 12th St, then used 12th St south to US 1. In this extension, SC 12 was placed on split one-way streets (Hampton/Taylor Sts) between Williams St and Park St.
In 1981, SC 12 was removed from 12th St (now SC 35) and extended as more new construction southwest to US 1.

SC 12 extended to SC 555 1958 Official

SC 12 extended to US 76 1959 Official

SC 12 extended to West Columbia 1977 Official

SC 12 extended to current end 1981 Official

Improvements: SC 12 was paved from Columbia out to SC 760 upon designation.
In 1941, SC 12 was paved several miles further east into Ft. Jackson.
All parts of SC 12 have been paved since 1948.
In 1963, SC 12 was multilane from US 76 east out through Forest Acres to its old route into Fort Jackson.
The 1977 and later extensions west from US 76 were multilane, including limited/controlled access west of US 21-176-321 to US 1.
The 2015 Official shows SC 12 multilane from Decker Blvd to I-77 Exit 15. GMSV shows this to be true back to at least 2008 and could go back to when I-77 was built through that area in the mid 1990s.
Comment: SC 12 serves as a quick way to access Downtown Columbia from US 1 in West Columbia, as well as provide access to Fort Jackson.
SC 12's routing to US 601 from Columbia doesn't make much sense with I-20 very close by, and even before that US 1 is not far north.
Strom Thurmond Blvd from Percival Rd to I-77 is labeled on City Maps as SC 12 SPUR though I do not believe there are any postings to that effect.

SC 12 Augusta to Columbia, throguh Moneta 1922 Auto Trails

SC 12 bypasses Moneta 1926 Official

US 1 replaces SC 12 1930 Official

SC 12 #2: Created as new primary routing in 1929 connecting SC 26 (now US 521) to nearby NC 25 (now NC 75).
In 1938, SC 12 was renumbered as SC 75.

SC 12 1930 Official

SC 75 replaces SC 12 1938 Official