The Highways of South Carolina US 378 
< US 321 | Home | US 401 >
US 378
From: US 501BUS Conway (Horry County)
To: Georgia State Line near Bakers Creek State Park (McCormick County)
Total Length: 208.3 miles  
Nationally, US 378 runs from Conway to US 78 Washington, GA.
ROUTE LOG
US 501 Bus: 0 - 0
SC 905: 0.8 - 0.8
US 501, US 701: 0.1 - 0.9
Marion-Horry Line: 11.5 - 12.4
SC 908: 5.1 - 17.5
SC 41 NB: 5.6 - 23.1
Florence-Marion Line: 1.9 - 25
SC 41 SB, SC 51 SB: 1.8 - 26.8
SC 51 NB: 3.3 - 30.1
US 378 Bus: 14.7 - 44.8
US 52: 1.2 - 46
US 378 Bus, SC 341: 2.4 - 48.4
Williamsburg-Florence Line: 3 - 51.4
Clarendon-Williamsburg Line: 2.4 - 53.8
US 301 NB: 7.8 - 61.6
SC 58: 0.4 - 62
US 301 SB: 0.1 - 62.1
Sumter-Clarendon Line: 3.4 - 65.5
I-95 (exit 135): 1.1 - 66.6
SC 53: 1.7 - 68.3
SC 527: 1.5 - 69.8
SC 763: 8.4 - 78.2
US 76 EB, US 76 Bus: 1.3 - 79.5
US 401: 0.9 - 80.4
US 15: 1.5 - 81.9
US 76 Bus, US 521: 2.6 - 84.5
SC 120: 0.3 - 84.8
SC 441: 7.2 - 92
SC 261: 1.7 - 93.7
Richland-Sumter Line: 6.1 - 99.8
SC 263: 1.2 - 101
US 601: 1.7 - 102.7
SC 764: 5.1 - 107.8
SC 769: 4.5 - 112.3
SC 768: 4.5 - 116.8
I-77 (exit 9): 1.9 - 118.7
SC 262: 0.1 - 118.8
SC 760: 1.6 - 120.4
SC 16: 0.2 - 120.6
US 1 NB: 2.3 - 122.9
SC 277: 0.9 - 123.8
SC 48: 0.4 - 124.2
US 21, US 176, US 321: 0.6 - 124.8
Lexington-Richland Line: 0.4 - 125.2
US 1 SB: 0.3 - 125.5
SC 2: 0.1 - 125.6
SC 12: 0.1 - 125.7
SC 35: 1.3 - 127
I-26 (exit 110): 2 - 129
I-20 (exit 61): 2.5 - 131.5
SC 6 WB: 5.6 - 137.1
SC 6 EB: 0.3 - 137.4
US 1 NB: 1 - 138.4
US 1 SB: 0.7 - 139.1
Saluda-Lexington Line: 14.4 - 153.5
SC 391: 3 - 156.5
SC 194: 13.5 - 170
US 178, SC 39, SC 121: 0.1 - 170.1
Edgefield-Saluda Line: 7.6 - 176.7
SC 430: 3 - 179.7
US 25: 6.9 - 186.6
SC 67: 4 - 190.6
McCormick-Edgefield Line: 2.2 - 192.8
US 221 NB: 7.9 - 200.7
US 221 SB, SC 28: 0.6 - 201.3
GA STATE LINE: 7 - 208.3
Creation: Appeared in 1951 or 1952 running more or less the way it does now. US 378 replaced: SC 43 from Georgia to West Columbia; SC 54 from Sumter to Kingsville; SC 90 from SC 41 to Conway. West Columbia to Sumter were multiplexes with US 1 and US 76.
Adjustments: Between 1957-58, US 378 received its Lake City Bypass as new Super-2 construction. The old route through town became US 378 Business.
Between 1959-61, US 378 received its freeway bypass of Sumter. The old route through Sumter became US 378 Business, which has since been decommissioned to SC 763 and US 76 Business.
Improvements: Fully paved upon designation.
The first multilane section of US 378 was in place by 1952, from the US 1 split in West Columbia east to SC 262.
The next section to be upgraded was from SC 262 east to SC 263 and from SC 441 to Sumter, both between 1957-58.
By 1964, US 378 was 4-lane from about today's SC 35 to the east end of the Sumter Bypass, except for the Wateree River causeway.
In 1971 or 1972, US 378 was four laned out from SC 35 to I-26 and also over the Wateree River.
In 1973, US 378 was 4-laned between I-20 and I-26.
Between 1974-77, US 378 was 4-laned from east Sumter to US 301 Turbeville. Also, the last 2 miles into Conway were multilaned.
Between 1978-79, US 378 was 4-laned from I-20 to Lexington.
In 1997, US 378 was 4-laned from Lexington west to S-32-204.
In 2001 or 2002, US 378 was 4-laned from S-32-204 west to S-32-24 (old SC 113) in western Lexington County. This made US 378 multilane continuously from S-32-24 to US 301 Turbeville, about 85 miles in all.
The Lake City bypass may have been 4-laned in 2004.
Comment: US 378 essentially slices South Carolina in half, serving a number of county seats - McCormick, Saluda, Lexington, Columbia, Sumter, and Conway.
US 378's junction with SC 391 is the most rural traffic circle I personally know of - miles from any real towns.
US 378 can be used as a viable, but 2-lane alternative to reach the Grand Strand.

 
 
US 701 BUSINESS
From: US 378SC 341 Lake City (Florence County)
To: US 378 Lake City (Florence County)
Total Length: 4.4 miles  
ROUTE LOG
US 378, SC 341 WB: 0 - 0
US 52: 2.1 - 2.1
SC 341 EB: 0.5 - 2.6
US 378: 1.8 - 4.4
Creation: Appeared in 1957 or 1958 when US 378 Bypass north of Lake City was built. This was of course mainline US 378 before that.
Adjustments: None
Improvements: Fully paved from inception with no multilane sections.
Comment: US 378 Business for Lake City uses Main St., N. Church St, and E. Myrtle Beach Hwy through the town.
US 378 Business was almost totally multiplexed with other routes in the beginning - SC 341 like today, and also US 52 Business (today's S-21-10).
US 378 Business was part of original SC 54.
US 378 Business  Decommissioned
Previous US 378 Business: US 378 Business: Appeared netween 1959-61 as Sumter was bypassed to the north. This route had been part of SC 54 and SC 3-SC 26 originally. Used Broad St, Liberty St. and Myrtle Beach Blvd. The Broad St and Liberty St sections were multilane by 1964.
Official Maps stopped showing Sumter in the 1970's. When Sumter was again included in the insets later in the 1980's, US 378 Business had been renumbered as an extended SC 763 east of town and retained its US 76 Business and US 521 designation northwest of town.

Last Update: 4 March 2005

Previous: US 321  |  Next: US 401
Top  |  South Carolina Hwy Index Home