US 176 east end, 1951-present
Goose Creek
US 178 east end, 1933-present
near Dorchester
Common: US 321 - US 601
Hardeeville. US 321 south end (1949-present); US 601 south end (1951-1996)
US 15 south end, 1951-present
Walterboro
US 278 east end, 1965-present
Hilton Head Island
US 21 south end, 1926-1935
near Yemassee
US 21 south end, 1935-1953
Beaufort (approx. location)
US 21 south end, 1953-present
Hunting Island. As of 2008 the "End" assembly is posted here, but this appears to be a truncation. "Satellite" view reveals a now-vacated road alignment south and east from here, which the USGS topo indicates once served as US 21. Presumably the highway went at least as far as the lighthouse, which is the cultural centerpiece of the state park, but I assume the road was later closed due to the high rate of beach erosion in this area (there is now a new road south of here that is used for state park access).
US 601 south end, 1996-present
near Pineland
US 52 south end, 1945-present
Charleston
US 78 east end, 1945-present
Charleston
US 701 south end, 1992-present
Georgetown
US 521 south end, 1933-present
Georgetown
US 501 south end, 1935-present
Myrtle Beach
Common: US 117 - US 501
Conway. US 117 south end (1932-1934); US 501 south end (1933-1935)
US 378 east end, 1952-present
Conway
Common: US 217 - US 301
Pee Dee. US 217 south end (1926-1933); US 301 south end (1933-1934)
US 601 north end, 1926-1933
near Cheraw
US 76 east end, 1926-1935
Florence
US 401 south end, 1957-present
Sumter
US 301 south end, 1934-1949
Summerton
US 123 north end, 1937-present
Greenville
US 276 east end, 1984-present
Mauldin
US 276 east end, 1932-1960(?)
Laurens
US 276 east end, 1960(?)-1965(?)
Clinton
US 276 east end, 1965(?)-1984
near Clinton
US 176 east end, 1926-1951
Newberry
US 321 south end, 1930-1949
Chester
US 178 west end, 1933-1937
Anderson
US 221 south end, 1932-1954
Greenwood
US 701 south end, 1937-1992
Charleston
US 76 west end, 1926-1932
Greenville
Common: US 17 - US 52 - US 701
Charleston. US 78 south end (1927-1945); US 701 south end (1932-1936); US 52 south end (1935-1945)
US 15 south end, 1935-1951
Walterboro (and if US 401[II] existed in 1933-1934, this was its south end as well.)
US 601 south end, 1926-1934
Florence