Total bridges
263
Public highway bridges in Guthrie County
County profile · official public datasets
Guthrie County, IA
263 public highway bridges tracked in the FHWA National Bridge Inventory: 24% rated Good, 39.2% Fair, 36.9% Poor.
- 263
- Public bridges
- 24%
- Good condition
- 36.9%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Guthrie County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- 92nd
- of 99 on Poor share
- 36.9%
- Poor-condition share
- 263
- public highway bridges
- 1976
- 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.
Guthrie County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Guthrie County ranks #92 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 36.9%). Guthrie County, Iowa contains 263 public highway bridges. Roughly 24% are rated “Good,” 39.2% “Fair,” and 36.9% “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.
Good condition
24%
63 of 263 rated 7-9
Fair condition
39.2%
103 of 263 rated 5-6
Poor condition
36.9%
97 of 263 rated 4 or below
In-state Poor-share rank
#92 of 99
Among Iowa counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 263 NBI-tracked bridges by lowest applicable component rating.
Good 24% (63)
Fair 39.2% (103)
Poor 36.9% (97)
Guthrie County's Poor-condition bridges carry 6,003 vehicle crossings a day
That is 9.3% of the county's reported daily bridge traffic on 36.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 63 crossings a day against 477 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 261 of 263 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
45.6% of Guthrie County's bridges have passed the 50-year mark
120 of the 263 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 24% 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 16.6% of the county's Poor-condition bridge traffic
F 65 over MIDDLE RIVER, built 1959, carries 996 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 97-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 6,003 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Guthrie County's bridges were built
263 bridges with a recorded construction year, grouped by decade
- 1910s 1
1910–1919
1 bridges
- 1920s 7
1920–1929
7 bridges
- 1930s 5
1930–1939
5 bridges
- 1940s
1940–1949
23 bridges
- 1950s
1950–1959
50 bridges
- 1960s 18
1960–1969
18 bridges
- 1970s
1970–1979
45 bridges
- 1980s
1980–1989
44 bridges
- 1990s
1990–1999
21 bridges
- 2000s 15
2000–2009
15 bridges
- 2010s
2010–2019
28 bridges
- 2020s 6
2020–2029
6 bridges
What this shows Construction peaked in the 1950s, when 50 of the county's bridges still in the inventory were built, which is 19% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year (1976) matches the Iowa average (1979).
How Guthrie County compares with Iowa's closest counties by inventory size
The 5 Iowa counties nearest Guthrie County in number of bridges, with their condition splits. Its 36.9% Poor share is the 6th-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1978 is in line with the group.
Showing the 5 closest of 98 Iowa counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Kossuth County | 267 | 44.6% | 39% | 16.5% | 1987 |
| Bremer County | 266 | 51.9% | 36.1% | 12% | 1990 |
| Cerro Gordo County | 266 | 44% | 51.1% | 4.9% | 1975 |
| O'Brien County | 264 | 51.9% | 43.2% | 4.9% | 1976 |
| Guthrie County (this page) | 263 | 24% | 39.2% | 36.9% | 1976 |
| Clayton County | 256 | 30.5% | 59% | 10.5% | 1964 |
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 Guthrie 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 Guthrie County, both outside Iowa so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IA (263 bridges here).
- Douglas County, CO · 263 bridges
- Bingham County, ID · 263 bridges
- Henry County, MO · 263 bridges
- Sequoyah County, OK · 263 bridges
Similar average build year
Nearest mean year-built outside IA (1976 here).
- Marion County, IN · avg 1976 · 958 bridges
- Mohave County, AZ · avg 1976 · 641 bridges
- Comanche County, OK · avg 1976 · 593 bridges
- Prince George's County, MD · avg 1976 · 576 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (103)
Read our methodology - how this data is sourced, computed, and verified.
Related
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.