County profile · official public datasets

Jefferson County, IA

157 public highway bridges tracked in the FHWA National Bridge Inventory: 43.9% rated Good, 37.6% Fair, 18.5% Poor.

157
Public bridges: 43.9%
Good condition: 18.5%
Poor condition

The verdict

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

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

Top 47%
lowest Poor share in state: 18.5%
Poor-condition share: 157
public highway bridges: 1983
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.

Jefferson County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Jefferson County ranks #47 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 18.5%). Jefferson County, Iowa contains 157 public highway bridges. Roughly 43.9% are rated “Good,” 37.6% “Fair,” and 18.5% “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

157

Public highway bridges in Jefferson County

Good condition

43.9%

69 of 157 rated 7-9

Fair condition

37.6%

59 of 157 rated 5-6

Poor condition

18.5%

29 of 157 rated 4 or below

In-state Poor-share rank

#47 of 99

Among Iowa counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 157 NBI-tracked bridges by lowest applicable component rating.

Good

43.9% (69)

Fair

37.6% (59)

Poor

18.5% (29)

Jefferson County's Poor-condition bridges carry 4,683 vehicle crossings a day

That is 4% of the county's reported daily bridge traffic on 18.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 161 crossings a day against 1,060 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 157 of 157 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

39.5% of Jefferson County's bridges have passed the 50-year mark

62 of the 157 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 43.9% 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 44.8% of the county's Poor-condition bridge traffic

E BURLINGTON AVE over WEST CROW CREEK, built 1954, carries 2,100 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 29-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 4,683 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

4
1910s

2
1920s

3
1930s

1
1940s

2
1950s

26
1960s

14
1970s

18
1980s

16
1990s

8
2000s

30
2010s

28
2020s

5

What this shows Construction peaked in the 2000s, when 30 of the county's bridges still in the inventory were built, which is 19.1% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year (1983) matches the Iowa average (1979).

How Jefferson County compares with Iowa's closest counties by inventory size

The 5 Iowa counties nearest Jefferson County in number of bridges, with their condition splits. Its 18.5% Poor share is the 3rd-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1980 is in line with the group.

Showing the 5 closest of 98 Iowa counties eligible for comparison.

Bridge inventory size and condition shares for Jefferson County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Wayne County	163	44.2%	37.4%	18.4%	1989
Monona County	162	36.4%	38.3%	25.3%	1973
Jefferson County (this page)	157	43.9%	37.6%	18.5%	1983
Buena Vista County	156	35.9%	32.7%	31.4%	1979
Van Buren County	156	23.7%	44.9%	31.4%	1975
Clay County	151	35.8%	54.3%	9.9%	1982

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 Jefferson 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 Jefferson County, both outside Iowa so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside IA (157 bridges here).

Lowndes County, AL · 157 bridges
Franklin County, MS · 157 bridges
Washington County, MO · 157 bridges
Stark County, ND · 157 bridges

Similar average build year

Nearest mean year-built outside IA (1983 here).

Dallas County, TX · avg 1983 · 3,230 bridges
Bexar County, TX · avg 1983 · 2,342 bridges
Sedgwick County, KS · avg 1983 · 1,333 bridges
Will County, IL · avg 1983 · 649 bridges

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

All 157 Good 69 Fair 59 Poor 29

Fair-condition bridges (59)

Sort:

Jefferson County Bridge Snapshot

Condition distribution

Jefferson County's Poor-condition bridges carry 4,683 vehicle crossings a day

39.5% of Jefferson County's bridges have passed the 50-year mark

One structure carries 44.8% of the county's Poor-condition bridge traffic

How Jefferson County compares with Iowa'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 (59)

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