SC 40 from Mt Pleasant to NC 1922 Auto Trails

US 701 replaces SC 40 1933 Official

Adjustments:
In 1935, US 17 was added as a multiplex from Georgetown down to Charleston.
In 1947, US 52 was moved to Meeting St, so US 701's south end was moved from Columbus and King to Meeting at Lee.
In late 1952, US 701 was rerouted from Tabor City to come south through Loris to get to Conway. This eliminated SC 904 and was also some new primary routing. The old routing became today's SC 410. The new routing was 3 miles shorter.

US 701 via Green Sea 1951 Official

US 701 via Loris 1953 NC Official

About 1957, US 701 was given its Tabor City bypass. The old route through town may have been secondary for a while (per Columbus County NC maps) but by 1962 was US 701 Business.

US 701 through Tabor City 1952 Horry County

US 701 bypasses Tabor City 1962 Horry County

As early as 1959, US 701 was given its bypass of Conway (county maps up through at least 2005 still erroneously show it going downtown) by following US 501 Bus NB on 16th St to the US 501 ypass south around Conway. The old route through Conway became US 501 Bus and SC 905.
About 1967, US 701 was rerouted onto the newly constructed Mt. Pleasant Bypass, leaving behind US 17-701 Business (I-526 spur and part of SC 703 today).

US 17 through Mt. Pleasant 1960 Charleston County

US 17 Bus through Mt. Pleasant 1967 Charleston County

US 17 Bus replaced by SC 703 and I-526 Bus 1996 Charleston County

In 1992, US 701 south was truncated to its current Georgetown end, leaving behind US 17 (the longtime US 701 crossing from Mt Pleasant to Charleston was closed in 2005 and torn down). On the Charleston side it is just Lee St. now.
Improvements: Fully paved except for between Homewood and Green Sea when created in 1932; fully paved in 1934.
The first multilane section of US 701 appeared in 1958, on the south side of Mt. Pleasant around Shem Creek.
In 1961, US 701 became multilane between Conway and Homewood and whenever it was added to 16th St and US 501 Bypass.
The next section to be upgraded was Charleston through the Mt. Pleasant Bypass in 1967.
In 1970, US 701 was 4-laned from the north end of the Mt. Pleasant Bypass to SC 41.
In 1974, US 701 was 4-laned around Awendaw; also Conway a short distance south.
In 1976, US 17 was 4-laned from Georgetown south for several miles.
In 1978, US 17 was 4-laned from from SC 41 to Awendaw and also from the Santee River Bridges north to Georgetown.
In 1979, US 17 was 4-laned from Mclellanville to the Santee River.
In 1980, US 17 was 4-laned from Awendaw to McLellanville.
In 1981, US 701 was multilaned from Georgetown to SC 51.
Of course, with the elimination of 60 miles of US 701, only a handful of miles are multilane today.
Comment: US 701 is a quiet ride west of the Waccamaw River, and can be used as part of an overall Grand Strand Bypass (along with SC 90).
US 701 was already not well posted south of Georgetown by the mid-70's. There were no US 701 signs on I-26, but there was one on a BGS at the US 17 Business split to Mt. Pleasant. The last SB sign used to be at the foot of the Mount Pleasant side of the Cooper River Bridge.
After the truncation, the SB sign near Charleston remained for a time, and a US 701 shield remained past the year 2000 (gone now) on US 52 NB a few blocks north of the end of I-26 (the shield directed a right turn to go back to US 17-701 via Morrison Dr). Up through 2011 (gone by 2015) there was still a small overhead green sign at the jct of US 17-17A-701 in Georgetown (you see it on US 17 SB approaching the intersection) saying US 17-701 to Charleston.
US 701 really hasn't been rebuilt that much, especially on its current routing.