SC 20 ending at Green/Guess 1922 Auto Trails

SC 20 ending at Green/Pendleton 1926 Auto Trails

If SC 20 ever used the lengthy S-23-245 from Gantt southward it stopped doing so by 1929.
It appears SC 20 was removed from today's S-4-389 between Honea Path and Belton about 1930.
SC 20 used S-33-93 and S-33-101 in the Parksville and Plum Branch areas originally. It appears it stopped doing so no later than 1933.
By 1935, SC 20 was removed from S-33-139 north of Plum Branch.
In 1935, SC 20 north was truncated to US 29 (current US 29-SC 20 CONN) S. Williamston. The route from there to Greenville became part of US 29, though today it is mostly again SC 20.
In 1936 or 1937, SC 20 was rerouted to avoid downtown McCormick, leaving behind SC 20 ALT (now S-33-11).

SC 20 into McCormick 1935 Official

SC 20 routed around McCormick 1937 Official

In 1938, SC 20 south was truncated to SC 28 (now SC 71) Abbeville, replaced by SC 28. This is still SC 28 except south out of Abbeville used S-1-1, SC 72, and SC 28-72 CONN.

SC 20 and SC 18 from Augusta to Anderson 1922 Auto Trails

SC 28 from Augusta to Anderson 1930 Official

In 1956, SC 20 was rerouted between Due West and Belton to its current routing. This replaced SC 257 and some of SC 284. The old route became part of SC 184 and the US 178 piece remained so.

SC 257 and SC 284 from Due West to Belton 1942 Official

SC 20 replaces SC 257 and SC 284 1956 Official

Also in 1956, SC 20 was re-extended north replacing US 29 through Williamston and Piedmont, ending at US 29 Businees (now US 29) south of Greenville.

SC 20 from Abbeville to Greenville 1922 Auto Trails

US 29 replaces SC 20 north of Williamston 1935 Official

SC 20 replaces US 29 to Greenville 1956 Official

In 1960, SC 20 was extended north along Grove Ave to end at US 25 (unnumbered now) Augusta Rd. This replaced US 29 Business.
About 1962, SC 20's south end was moved onto the newly constructed Abbeville bypass to end at SC 28/SC 28 Bus northwest of town. SC 20 into Abbeville was downgraded to S-1-2.
Between 1971-75, SC 20 was put back through Abbeville by replacing S-1-2 and what I think was SC 71 to its current SC 72 endpoint. The old route over to SC 28 became SC 20-28 CONN.

SC 20 to Abbeville 1958 Abbeville County

SC 20 avoids Abbeville 1966 Abbeville County

SC 20 back through Abbeville again 1975 Abbeville County

Between 1998-1999, SC 20 was extended north to US 123, replacing part of US 25 Business.

US 29 Business into Greenville 1957 Official

SC 20 replaces US 29 Business into Greenville 1960 Official

SC 20 replaces US 25 Business into downtown Greenville 1999 Official

Improvements: SC 20 was paved only from Greenville south a few miles by 1928.
In 1929, SC 20 was paved from Greenville to Pelzer and from Belton to Honea Path.
In 1930, SC 20 was paved from Pelzer to Williamston.
In 1931, SC 20 was paved from Honea Path down to Abbeville.
In 1933, SC 20 was paved from Modoc to the Georgia Line.
In 1934, SC 20 was paved everywhere except Williamston to Belton and McCormick to Plum Branch.
In 1935, McCormick to Plum Branch was paved.
In 1936, SC 20 became fully paved.
SC 20's northernmost 2 miles were multilaned by 1974.
When SC 20 was extended over old US 25 Business in Greenville, that was 4-laned as well.
In 2005, SC 20 was multilaned south to I-185 TOLL.
Comment: SC 20 serves some rural, small town areas between Abbeville and Greenville, including Due West, home of Erskine College.
There is a posted SC 20 TRUCK route that runs along SC 72, SC 28, and the SC 20-28 CONN to form a huge loop around Abbeville.