SC 97 ALT: Appeared in 1931 as a renumbering of a rerouted SC 97, running from SC 97 Beckhamville southeast to SC 22 (now S-12-20/62 jct) Great Falls.
By 1942, SC 97 ALT east was truncated to SC 5 (now US 21) leaving behind SC 22 ALT (now S-12-20).
In 1949, SC 97 ALT was renumbered as part of SC 99.

SC 97 into Great Falls 1926 Official

SC 97 avoids Great Falls, leaving behind SC 97 ALT 1932 Official

SC 97 ALT shortened to cutoff between SC 5 and SC 97. 1942 Chester County

SC 97 ALT renumbered as SC 99 1952 Chester County