County profile · official public datasets

Winneshiek County, IA

342 public highway bridges tracked in the FHWA National Bridge Inventory: 37.1% rated Good, 45.3% Fair, 17.5% Poor.

342
Public bridges: 37.1%
Good condition: 17.5%
Poor condition

The verdict

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

Winneshiek 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 43%
lowest Poor share in state: 17.5%
Poor-condition share: 342
public highway bridges: 1967
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.

Winneshiek County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Winneshiek County ranks #43 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 17.5%). Winneshiek County, Iowa contains 342 public highway bridges. Roughly 37.1% are rated “Good,” 45.3% “Fair,” and 17.5% “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

342

Public highway bridges in Winneshiek County

Good condition

37.1%

127 of 342 rated 7-9

Fair condition

45.3%

155 of 342 rated 5-6

Poor condition

17.5%

60 of 342 rated 4 or below

In-state Poor-share rank

#43 of 99

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

Condition distribution

Share of 342 NBI-tracked bridges by lowest applicable component rating.

Good

37.1% (127)

Fair

45.3% (155)

Poor

17.5% (60)

Winneshiek County's Poor-condition bridges carry 6,490 vehicle crossings a day

That is 4.4% of the county's reported daily bridge traffic on 17.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 108 crossings a day against 396 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 341 of 342 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

50.9% of Winneshiek County's bridges have passed the 50-year mark

174 of the 342 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 37.1% 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 14.7% of the county's Poor-condition bridge traffic

FM over TROUT RIVER, built 1956, carries 953 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 60-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 6,490 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

1
1900s

53
1910s

6
1920s

4
1930s

9
1940s

6
1950s

24
1960s

50
1970s

53
1980s

33
1990s

28
2000s

37
2010s

33
2020s

5

What this shows Construction peaked in the 1900s, when 53 of the county's bridges still in the inventory were built, which is 15.5% of those with a recorded year. That cohort is now 115 to 124 years old in the 2024 inventory. Its average build year is 1967, 12 years older than the Iowa average of 1979.

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

The 5 Iowa counties nearest Winneshiek County in number of bridges, with their condition splits. Its 17.5% Poor share is the 4th-lowest of these 6. Its average build year of 1967 against a peer-group mean of 1982 is 15 years older.

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

Bridge inventory size and condition shares for Winneshiek County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Clinton County	372	66.7%	30.4%	3%	1986
Fayette County	362	35.1%	40.3%	24.6%	1974
Dubuque County	346	50.6%	40.8%	8.7%	1989
Winneshiek County (this page)	342	37.1%	45.3%	17.5%	1967
Tama County	337	34.4%	31.2%	34.4%	1976
Buchanan County	316	42.4%	50.9%	6.6%	1985

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

Similar inventory size

Nearest county inventories outside IA (342 bridges here).

Stephenson County, IL · 342 bridges
Noble County, OK · 342 bridges
Wayne County, IN · 343 bridges
Norfolk County, MA · 343 bridges

Similar average build year

Nearest mean year-built outside IA (1967 here).

Los Angeles County, CA · avg 1967 · 3,547 bridges
Allegheny County, PA · avg 1967 · 1,294 bridges
Sonoma County, CA · avg 1967 · 609 bridges
Merced County, CA · avg 1967 · 528 bridges

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

All 342 Good 127 Fair 155 Poor 60

Fair-condition bridges (155)

Sort:

Winneshiek County Bridge Snapshot

Condition distribution

Winneshiek County's Poor-condition bridges carry 6,490 vehicle crossings a day

50.9% of Winneshiek County's bridges have passed the 50-year mark

One structure carries 14.7% of the county's Poor-condition bridge traffic

How Winneshiek 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 (155)

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