County profile · official public datasets

Darlington County, SC

174 public highway bridges tracked in the FHWA National Bridge Inventory: 32.8% rated Good, 62.1% Fair, 5.2% Poor.

174
Public bridges: 32.8%
Good condition: 5.2%
Poor condition

The verdict

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

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

Top 48%
lowest Poor share in state: 5.2%
Poor-condition share: 174
public highway bridges: 1974
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.

Darlington County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Darlington County ranks #22 of 46 South Carolina counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 5.2%). Darlington County, South Carolina contains 174 public highway bridges. Roughly 32.8% are rated “Good,” 62.1% “Fair,” and 5.2% “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

174

Public highway bridges in Darlington County

Good condition

32.8%

57 of 174 rated 7-9

Fair condition

62.1%

108 of 174 rated 5-6

Poor condition

5.2%

9 of 174 rated 4 or below

In-state Poor-share rank

#22 of 46

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

Condition distribution

Share of 174 NBI-tracked bridges by lowest applicable component rating.

Good

32.8% (57)

Fair

62.1% (108)

Poor

5.2% (9)

Darlington County's Poor-condition bridges carry 22,600 vehicle crossings a day

That is 3.6% of the county's reported daily bridge traffic on 5.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 2,511 crossings a day against 3,389 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 174 of 174 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

62.6% of Darlington County's bridges have passed the 50-year mark

109 of the 174 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 32.8% 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 31% of the county's Poor-condition bridge traffic

SC 34 over SWIFT CREEK, built 1939, carries 7,000 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 9-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 22,600 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

4
1930s

15
1940s

5
1950s

13
1960s

37
1970s

43
1980s

10
1990s

17
2000s

12
2010s

12
2020s

6

What this shows Construction peaked in the 1970s, when 43 of the county's bridges still in the inventory were built, which is 24.7% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1974) matches the South Carolina average (1977).

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

The 5 South Carolina counties nearest Darlington County in number of bridges, with their condition splits. Its 5.2% Poor share is the 4th-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1975 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 Darlington County and the 5 South Carolina counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Lancaster County	181	29.3%	58%	12.7%	1967
Kershaw County	174	39.7%	55.2%	5.2%	1978
Darlington County (this page)	174	32.8%	62.1%	5.2%	1974
Clarendon County	170	25.3%	72.9%	1.8%	1976
Sumter County	166	44%	45.2%	10.8%	1981
Abbeville County	163	41.1%	55.8%	3.1%	1975

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 Darlington 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 Darlington County, both outside South Carolina so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside SC (174 bridges here).

Hempstead County, AR · 174 bridges
Eagle County, CO · 174 bridges
Washington County, IN · 174 bridges
Lac qui Parle County, MN · 174 bridges

Similar average build year

Nearest mean year-built outside SC (1974 here).

Knox County, TN · avg 1974 · 588 bridges
Summit County, OH · avg 1974 · 563 bridges
Onondaga County, NY · avg 1974 · 472 bridges
Orange County, NY · avg 1974 · 472 bridges

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

All 174 Good 57 Fair 108 Poor 9

All bridges (174)

Sort:

Darlington County Bridge Snapshot

Condition distribution

Darlington County's Poor-condition bridges carry 22,600 vehicle crossings a day

62.6% of Darlington County's bridges have passed the 50-year mark

One structure carries 31% of the county's Poor-condition bridge traffic

How Darlington 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 (174)

S-16-255

S-16-19

S-16-269

C-16-735

US 52

US 401

US 401

US 15

US 15 BUS

S-16-892

S-16-41

S-16-50

S-16-13

S-16-23

S-16-290

S-16-35

S-16-19

S-16-28

S-16-19

S-16-185

S-16-18

US 52

US 401

US 52

US 52

US 15

US 52

S-16-16

US 52 BUS

S-16-44

US 15

US 52 EBL

S-16-32

US 15

S-16-133

S-16-35

S-16-30

S-16-13

I-20 WB

I-20 WB

I-20 EB

I-20 EB

I-20 EB

US 52

S-16-290

S-16-131

S-16-355

I-20 EB

I-20 EB

I-20 WB

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