County profile · official public datasets

Dillon County, SC

128 public highway bridges tracked in the FHWA National Bridge Inventory: 25% rated Good, 70.3% Fair, 4.7% Poor.

128
Public bridges: 25%
Good condition: 4.7%
Poor condition

The verdict

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

Dillon County pairs a better-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 41%
lowest Poor share in state: 4.7%
Poor-condition share: 128
public highway bridges: 1972
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.

Dillon County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Dillon County ranks #19 of 46 South Carolina counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.7%). Dillon County, South Carolina contains 128 public highway bridges. Roughly 25% are rated “Good,” 70.3% “Fair,” and 4.7% “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

128

Public highway bridges in Dillon County

Good condition

25%

32 of 128 rated 7-9

Fair condition

70.3%

90 of 128 rated 5-6

Poor condition

4.7%

6 of 128 rated 4 or below

In-state Poor-share rank

#19 of 46

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

Condition distribution

Share of 128 NBI-tracked bridges by lowest applicable component rating.

Good

25% (32)

Fair

70.3% (90)

Poor

4.7% (6)

Dillon County's Poor-condition bridges carry 58,750 vehicle crossings a day

That is 10.2% of the county's reported daily bridge traffic on 4.7% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 9,792 crossings a day against 1,548 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 128 of 128 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

67.2% of Dillon County's bridges have passed the 50-year mark

86 of the 128 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 25% 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 37.2% of the county's Poor-condition bridge traffic

I-95 NB over LITTLE REEDY CREEK, built 1965, carries 21,850 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 6-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 58,750 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

2
1930s

4
1940s

9
1950s

4
1960s

61
1970s

15
1980s

12
1990s

8
2000s

4
2010s

8
2020s

1

What this shows Construction peaked in the 1960s, when 61 of the county's bridges still in the inventory were built, which is 47.7% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1972, 5 years older than the South Carolina average of 1977.

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

The 5 South Carolina counties nearest Dillon County in number of bridges, with their condition splits. Its 4.7% Poor share is the 3rd-lowest of these 6. Its average build year of 1972 against a peer-group mean of 1973 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 Dillon County and the 5 South Carolina counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Fairfield County	139	36.7%	55.4%	7.9%	1976
Union County	131	35.9%	49.6%	14.5%	1975
Jasper County	129	24.8%	75.2%	0%	1970
Dillon County (this page)	128	25%	70.3%	4.7%	1972
Saluda County	125	40.8%	52.8%	6.4%	1973
Edgefield County	124	34.7%	62.9%	2.4%	1972

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

Similar inventory size

Nearest county inventories outside SC (128 bridges here).

Custer County, ID · 128 bridges
Franklin County, ME · 128 bridges
Harper County, OK · 128 bridges
Cheatham County, TN · 128 bridges

Similar average build year

Nearest mean year-built outside SC (1972 here).

Santa Clara County, CA · avg 1972 · 964 bridges
Madison County, AL · avg 1972 · 710 bridges
Kern County, CA · avg 1972 · 668 bridges
York County, PA · avg 1972 · 569 bridges

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

All 128 Good 32 Fair 90 Poor 6

Fair-condition bridges (90)

Sort:

Dillon County Bridge Snapshot

Condition distribution

Dillon County's Poor-condition bridges carry 58,750 vehicle crossings a day

67.2% of Dillon County's bridges have passed the 50-year mark

One structure carries 37.2% of the county's Poor-condition bridge traffic

How Dillon 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

Fair-condition bridges (90)

S-17-58

SC 57

S-17-45

S-17-745

US 301

S-17-323

S-17-198

I-95 NB

SC 57

SC 41

S-17-29

S-17-60

S-17-23

SC 41

SC 34

SC 917

I-95 NB

SC 57

I-95 SB

S-17-23

I-95 NB

I-95 SB

S-17-61

S-17-286

I-95 NB

I-95 SB

I-95 SB

I-95 NB

I-95 NB

I-95 SB

I-95 SB

SC 9

SC 9

S-17-198

I-95 SB

I-95 NB

I-95 NB

I-95 SB

I-95 NB

I-95 SB

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