County profile · official public datasets

Poweshiek County, IA

248 public highway bridges tracked in the FHWA National Bridge Inventory: 25% rated Good, 33.1% Fair, 41.9% Poor.

248
Public bridges: 25%
Good condition: 41.9%
Poor condition

The verdict

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

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

96th
of 99 on Poor share: 41.9%
Poor-condition share: 248
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.

Poweshiek County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Poweshiek County ranks #96 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 41.9%). Poweshiek County, Iowa contains 248 public highway bridges. Roughly 25% are rated “Good,” 33.1% “Fair,” and 41.9% “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

248

Public highway bridges in Poweshiek County

Good condition

25%

62 of 248 rated 7-9

Fair condition

33.1%

82 of 248 rated 5-6

Poor condition

41.9%

104 of 248 rated 4 or below

In-state Poor-share rank

#96 of 99

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

Condition distribution

Share of 248 NBI-tracked bridges by lowest applicable component rating.

Good

25% (62)

Fair

33.1% (82)

Poor

41.9% (104)

Poweshiek County's Poor-condition bridges carry 29,632 vehicle crossings a day

That is 10.5% of the county's reported daily bridge traffic on 41.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 285 crossings a day against 1,170 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 248 of 248 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

52.8% of Poweshiek County's bridges have passed the 50-year mark

131 of the 248 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 44.9% of the county's Poor-condition bridge traffic

I 80 WB over IOWA 21, built 1963, carries 13,300 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 104-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 29,632 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

4
1920s

12
1930s

1
1940s

8
1950s

48
1960s

47
1970s

32
1980s

36
1990s

12
2000s

26
2010s

9
2020s

13

What this shows Construction peaked in the 1950s, when 48 of the county's bridges still in the inventory were built, which is 19.4% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year is 1974, 5 years older than the Iowa average of 1979.

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

The 5 Iowa counties nearest Poweshiek County in number of bridges, with their condition splits. Its 41.9% Poor share is the 6th-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1978 is in line with the group.

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

Bridge inventory size and condition shares for Poweshiek County and the 5 Iowa counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Carroll County	249	48.6%	44.6%	6.8%	1977
Cherokee County	248	34.3%	36.7%	29%	1968
Poweshiek County (this page)	248	25%	33.1%	41.9%	1974
Jackson County	246	26.4%	56.5%	17.1%	1983
Hardin County	241	36.1%	36.1%	27.8%	1981
Iowa County	241	37.3%	43.6%	19.1%	1980

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

Similar inventory size

Nearest county inventories outside IA (248 bridges here).

Crawford County, AR · 248 bridges
Lowndes County, MS · 248 bridges
Herkimer County, NY · 248 bridges
Rockland County, NY · 248 bridges

Similar average build year

Nearest mean year-built outside IA (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 248 Good 62 Fair 82 Poor 104

All bridges (248)

Sort:

Poweshiek County Bridge Snapshot

Condition distribution

Poweshiek County's Poor-condition bridges carry 29,632 vehicle crossings a day

52.8% of Poweshiek County's bridges have passed the 50-year mark

One structure carries 44.9% of the county's Poor-condition bridge traffic

How Poweshiek 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

All bridges (248)

LOCAL

WEBSTER ST

US 6 & IA 21

I-80

FM

EB I-80

US 63

FM

LOCAL

FM

FM

FM

FM

WB I-80

LOCAL

LOCAL

FM

LOCAL

FM

FM

IA 146

I-80

IA 21

US 63

FM

LOCAL

FM

IA 21

US 63

LOCAL

LOCAL

IA 21

SR T-58

SR 200TH STREET

145TH ST

20TH ST

V30 240TH ST

LOCAL

EAST 156TH ST N

400TH ST

LOCAL

180TH ST

505TH AVE

LOCAL

IA 21

IA 21

I 80 EB

I 80 WB

I 80 EB

I 80 WB

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