SC 646: Appeared in 1942 as new primary routing from SC 28 (now SC 125) near Hattieville north via Meyers Mill to end at SC 64 (now SRS Route B) near Dunbarton.
In 1946, SC 646 was downgraded to S-6-28. Today SC 646 is within the Savannah River Site and is SRS Route 9.
