US 217 Pee Dee to NC 1930 Official

US 301 usurps US 217 1933 Official

Adjustments: In 1935, US 301 was extended south by following US 76 west to Florence and US 52 south to Effingham, then replaced SC 4 to US 15 Summerton.

SC 4 Effingham southwestward 1933 Official

US 301 replaces SC 4 to Summerton 1935 Official

Between 1944-47, US 301 was given its current more direct routing across the Great Pee Dee River. The old route is 2 miles abandoned alignment on the Marion County side and on the Florence County side it is a little S-21-24 plus private Dupont Rd.

US 301 dipping to Mars Bluff Bridge 1940 Florence County

US 301 on direct routing to the river 1947 Florence County

In 1947, US 301 was extended south with US 15 to Santee, then replaced SC 4 to Orangeburg; SC 33 through Bamberg to Ulmers; replaced SC 508 to Allendale; and replaced SC 73 to Georgia.

various state routes Santee to Allendale 1942 Official

US 301 extended to Georgia 1948 Official

In 1948, US 301 was removed from Cheves St and placed on Palmetto Ave leaving US 52 Irby St in Florence. Cheves St became S-21-92.

US 301 using Palmetto-Irby-Cheves 1940 Florence County

US 301 on Palmetto all the way 1950 Florence County

In 1954, US 301 was rerouted in Orangeburg to its current path as new routing. This left behiind S-38-1 Dorchester Rd and an extended SC 33 through downtown Orangeburg.

US 301 via Dorchester Rd and Russell St 1951 Official

US 301 rerouted 1966 Official

In 1965, US 301 was placed on a new causeway approaching the Savannah River slightly west of the original and is nearly 3 miles long. The abandoned causeway is now a bike trail that can get onto but not all the way across the original 1940 bridge.
About 1970, US 301 was removed from S-17-630 at the North Carolina border to facilitate its interchange with I-95.
In 1987, US 301 was put onto I-95 between Exit 97 and Exit 102, over Lake Marion. The US 15-301 bridge over Lake Marion has been closed to traffic ever since. The road south of Lake Marion became S-38-430 and US 15/301-SC 6 CONN. The approach to I-95 north of the lake had been S-14-400 and the route connecting US 15-301 to I-95 Exit 97 had previously been I-95/US 301 CONN.

US 301 parallel to I-95 1986 Orangeburg County

US 301 moved onto I-95 over Lake Marion 1996 Orangeburg County

About 2007, US 301 was placed on newly constructed routing to bypass Florence to the east. The old route remains part of US 52 and US 76.

US 301 through Florence 2006 Official

US 301 bypasses Florence 2009 Official

Improvements: Paved upon designation
The first multilane sections of US 301 appeared in 1962: The entire US 76 multiplex; Orangeburg west to SC 4; the south side of Allendale
In 1963, US 301 was multilaned from Florence down to SC 51; I-26 west to Orangeburg; SC 641 to Allendale
In 1968 or 1969, US 301 was 4-laned from Latta to Dillon. Also, US 301 was 4-laned from SC 51 to Effingham
In 1967, maps began showing US 301 multilaned on its new Savannah Causeway in error.
In 1970, US 301 was multilaned from SC 70 to SC 4; also from the old Savannah River causeway to Allendale.
In 1971, US 301 was 4-laned between I-26 and SC 267.
In 1972, US 301 was 4-laned from SC 267 to I-95.
In 1973, US 301 was 4-laned from SC 70 to SC 641, making US 301 4-lane from I-95 all the way to just short of Georgia.
Obviously when US 301 was moved onto I-95 around Lake Marion in 1987, that made US 301 a freeway right there.
US 301's alignment around Florence was multilane upon opening in 2007.
Comment: US 301 serves South of the Border, the famous tourist trap with the tacky billboards up and down I-95. Note that this place actually dates back to the 40's as a beer stand (Robeson County, NC was dry back in the day) on US 301-501.
The original Lake Marion bridge for US 301 (which is not US 15's original bridge) is fully intact and can be bicycled/walked.
Unlike North Carolina and Virginia, US 301 in South Carolina actually gives I-95 some breathing room. On the other hand, US 301 is the same in that there are many old mom and pop businesses that are rotting away along its path.
Up until the early 90's there was giant billboard on I-95 SB in Santee with a giant "301 to Florida" banner. Just in case you felt the need to traverse inland swamps instead of coastal ones.
US 301 in Orangeburg passes right by Edisto Gardens, which is featured in photos on several official map issues.
US 301 is the longest US Route in S.C. with no business designations (at least for now!).