County profile · official public datasets

Williamsburg County, SC

195 public highway bridges tracked in the FHWA National Bridge Inventory: 38.5% rated Good, 54.9% Fair, 6.7% Poor.

195
Public bridges: 38.5%
Good condition: 6.7%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Williamsburg County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

31st
of 46 on Poor share: 6.7%
Poor-condition share: 195
public highway bridges: 1977
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

Williamsburg County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Williamsburg County ranks #31 of 46 South Carolina counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.7%). Williamsburg County, South Carolina contains 195 public highway bridges. Roughly 38.5% are rated “Good,” 54.9% “Fair,” and 6.7% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

Total bridges

195

Public highway bridges in Williamsburg County

Good condition

38.5%

75 of 195 rated 7-9

Fair condition

54.9%

107 of 195 rated 5-6

Poor condition

6.7%

13 of 195 rated 4 or below

In-state Poor-share rank

#31 of 46

Among South Carolina counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 195 NBI-tracked bridges by lowest applicable component rating.

Good

38.5% (75)

Fair

54.9% (107)

Poor

6.7% (13)

Williamsburg County's Poor-condition bridges carry 14,500 vehicle crossings a day

That is 6.5% of the county's reported daily bridge traffic on 6.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,115 crossings a day against 1,453 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 195 of 195 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

52.3% of Williamsburg County's bridges have passed the 50-year mark

102 of the 195 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 38.5% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 28.3% of the county's Poor-condition bridge traffic

SC 41 over BIG DAM SWAMP, built 1942, carries 4,100 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 13-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 14,500 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

1
1930s

9
1940s

11
1950s

13
1960s

55
1970s

21
1980s

12
1990s

39
2000s

23
2010s

9
2020s

2

What this shows Construction peaked in the 1960s, when 55 of the county's bridges still in the inventory were built, which is 28.2% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1977) matches the South Carolina average (1977).

How Williamsburg County compares with South Carolina's closest counties by inventory size

The 5 South Carolina counties nearest Williamsburg County in number of bridges, with their condition splits. Its 6.7% Poor share is the 3rd-lowest of these 6. Its average build year of 1977 against a peer-group mean of 1976 is in line with the group.

Showing the 5 closest of 45 South Carolina counties eligible for comparison.

Bridge inventory size and condition shares for Williamsburg County and the 5 South Carolina counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Cherokee County	199	45.2%	43.7%	11.1%	1983
Chesterfield County	199	40.2%	54.8%	5%	1974
Aiken County	198	36.9%	53.5%	9.6%	1977
Dorchester County	198	28.8%	69.2%	2%	1972
Williamsburg County (this page)	195	38.5%	54.9%	6.7%	1977
Chester County	190	40.5%	50%	9.5%	1976

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Williamsburg County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for Williamsburg County, both outside South Carolina so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside SC (195 bridges here).

Otero County, CO · 195 bridges
Lucas County, IA · 195 bridges
LaSalle County, LA · 195 bridges
Sabine County, LA · 195 bridges

Similar average build year

Nearest mean year-built outside SC (1977 here).

San Diego County, CA · avg 1977 · 1,632 bridges
King County, WA · avg 1977 · 1,238 bridges
Riverside County, CA · avg 1977 · 1,117 bridges
Shelby County, TN · avg 1977 · 1,077 bridges

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 195 Good 75 Fair 107 Poor 13

All bridges (195)

Sort:

Williamsburg County Bridge Snapshot

Condition distribution

Williamsburg County's Poor-condition bridges carry 14,500 vehicle crossings a day

52.3% of Williamsburg County's bridges have passed the 50-year mark

One structure carries 28.3% of the county's Poor-condition bridge traffic

How Williamsburg County compares with South Carolina's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (195)

S-45-385

S-45-186

C-45-641

S-45-48

S-45-16

S-45-35

S-45-574

S-45-90

S-45-40

S-45-86

S-45-319

L-45-469

S-45-639

SC 261

S-45-74

S-45-48

S-45-300

S-45-453

S-45-58

S-45-286

S-45-370

S-45-574

S-45-104

SC 527

SC 261

SC 261

S-45-33

SC 41

SC 512

S-45-197

S-45-526

S-45-573

SC 527

S-45-35

SC 512

S-45-271

S-45-85

US 521

S-45-496

S-45-24

SC 512

US 521

SC 261

SC 512

US 521

US 521

SC 527

US 521

S-45-24

S-45-35

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