County profile · official public datasets

O'Brien County, IA

264 public highway bridges tracked in the FHWA National Bridge Inventory: 51.9% rated Good, 43.2% Fair, 4.9% Poor.

264
Public bridges
51.9%
Good condition
4.9%
Poor condition

The verdict

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

O'Brien County posts a top-5% lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 5%
lowest Poor share in state
4.9%
Poor-condition share
264
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.

O'Brien County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, O'Brien County ranks #5 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.9%). O'Brien County, Iowa contains 264 public highway bridges. Roughly 51.9% are rated “Good,” 43.2% “Fair,” and 4.9% “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

264

Public highway bridges in O'Brien County

Good condition

51.9%

137 of 264 rated 7-9

Fair condition

43.2%

114 of 264 rated 5-6

Poor condition

4.9%

13 of 264 rated 4 or below

In-state Poor-share rank

#5 of 99

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

Condition distribution

Share of 264 NBI-tracked bridges by lowest applicable component rating.

Good
51.9% (137)
Fair
43.2% (114)
Poor
4.9% (13)

O'Brien County's Poor-condition bridges carry 2,284 vehicle crossings a day

That is 2.2% of the county's reported daily bridge traffic on 4.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 208 crossings a day against 377 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 262 of 264 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

44.7% of O'Brien County's bridges have passed the 50-year mark

118 of the 264 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 51.9% 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 76.2% of the county's Poor-condition bridge traffic

IA 10 over MUD CREEK, built 1951, carries 1,740 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 13-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 2,284 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When O'Brien County's bridges were built

264 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 2000s, when 40 of the county's bridges still in the inventory were built, which is 15.2% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year (1976) matches the Iowa average (1979).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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

The 5 Iowa counties nearest O'Brien County in number of bridges, with their condition splits. Its 4.9% Poor share is the 2nd-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.

Bridge inventory size and condition shares for O'Brien County and the 5 Iowa counties closest to it in inventory size
County Bridges Poor
Kossuth County 267 16.5%
Bremer County 266 12%
Cerro Gordo County 266 4.9%
O'Brien County (this page) 264 4.9%
Guthrie County 263 36.9%
Clayton County 256 10.5%

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

Similar inventory size

Nearest county inventories outside IA (264 bridges here).

Similar average build year

Nearest mean year-built outside IA (1976 here).

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

All 264 Good 137 Fair 114 Poor 13

Good-condition bridges (137)

LOCAL

Good

Over: LITTLE WATERMAN CR

096391902, O'Brien, IA

Built 1925 Load: 10.4 t ADT: 15

LOCAL

Good

Over: LITTLE WATERMAN CREEK

096393201, O'Brien, IA

Built 1952 Load: 17.8 t ADT: 35

420TH ST

Good

Over: BARRY CREEK

095 39 20 01, O'Brien, IA

Built 2011 Load: 18.8 t ADT: 71

NORTHWEST BLVD

Good

Over: FLOYD RIVER

097423006, O'Brien, IA

Built 1982 Load: 19.4 t ADT: 1,296

LOCAL

Good

Over: WEST BRANCH MILL CREEK

096412901, O'Brien, IA

Built 1966 Load: 20.1 t ADT: 46

FM

Good

Over: WATERMAN CREEK

097400102, O'Brien, IA

Built 1965 Load: 20.1 t ADT: 309

FM

Good

Over: PLESSIS CREEK

097402402, O'Brien, IA

Built 1964 Load: 20.1 t ADT: 309

LOCAL

Good

Over: FLOYD RIVER

097422101, O'Brien, IA

Built 1954 Load: 21.0 t ADT: 35

SILVER AVE

Good

Over: NELSON CREEK

09440180210, O'Brien, IA

Built 2016 Load: 21.4 t ADT: 45

FM

Good

Over: DRY RUN

095400605, O'Brien, IA

Built 1998 Load: 22.0 t ADT: 1,168

LOCAL SEC RD

Good

Over: DRAINAGE WAY

094421901, O'Brien, IA

Built 2008 Load: 22.7 t ADT: 30

LOCAL SEC RD

Good

Over: SMALL UN-NAMED CREEK

094421902, O'Brien, IA

Built 2006 Load: 22.7 t ADT: 30

LOCAL SEC RD

Good

Over: MCCREATH CR

095391602, O'Brien, IA

Built 2001 Load: 22.7 t ADT: 15

440TH ST

Good

Over: DRY RUN

095403301, O'Brien, IA

Built 2012 Load: 22.7 t ADT: 30

LOCAL

Good

Over: WILLOW CREEK

096393601, O'Brien, IA

Built 2004 Load: 22.7 t ADT: 11

LOCAL

Good

Over: SO BR LITTLE FLOYD RIVER

096411001, O'Brien, IA

Built 2002 Load: 22.7 t ADT: 5

IA 60

Good

Over: ENGELS CREEK

1.5 mi. N of US 18, O'Brien, IA

Built 2006 Load: 22.7 t ADT: 5,300

PIERCE AVE

Good

Over: W BR MILL CREEK

096412902, O'Brien, IA

Built 1966 Load: 23.0 t ADT: 15

450TH ST

Good

Over: MUD CREEK

094 41 06 01, O'Brien, IA

Built 2011 Load: 23.5 t ADT: 26

FM

Good

Over: WATERMAN CREEK

095391001, O'Brien, IA

Built 1953 Load: 24.3 t ADT: 797

FM

Good

Over: MILL CREEK

095412001, O'Brien, IA

Built 1985 Load: 24.5 t ADT: 50

300TH ST

Good

Over: PLESSIS CREEK

097402301, O'Brien, IA

Built 2017 Load: 25.3 t ADT: 21

LOCAL

Good

Over: MURRAY CREEK

094391505, O'Brien, IA

Built 1991 Load: 25.6 t ADT: 11

LOCAL SEC RD

Good

Over: DEEP CR

094421902, O'Brien, IA

Built 1989 Load: 25.9 t ADT: 30

LOCAL RD

Good

Over: NELSON CREEK

094401702, O'Brien, IA

Built 1990 Load: 26.6 t ADT: 50

FM

Good

Over: LANGE CR

094411702, O'Brien, IA

Built 1967 Load: 26.6 t ADT: 45

POLK AVE

Good

Over: SO BR LITTLE FLOYD RIVER

096410902, O'Brien, IA

Built 2015 Load: 26.6 t ADT: 30

LOCAL

Good

Over: SMALL UN-NAMED CREEK

094403102, O'Brien, IA

Built 1978 Load: 26.9 t ADT: 62

WARBLER AVE

Good

Over: JORDAN CREEK

09539330210, O'Brien, IA

Built 2016 Load: 26.9 t ADT: 26

LOCAL

Good

Over: LITTLE WATERMAN CREEK

096402502, O'Brien, IA

Built 2006 Load: 26.9 t ADT: 21

LOCAL

Good

Over: PLESSIS CREEK

097402501, O'Brien, IA

Built 1999 Load: 27.2 t ADT: 30

FM

Good

Over: LITTLE FLOYD RIVER

096421002, O'Brien, IA

Built 1987 Load: 27.3 t ADT: 1,337

LOCAL SEC RD

Good

Over: DRY RUN

094400502, O'Brien, IA

Built 1949 Load: 27.6 t ADT: 21

LOCAL

Good

Over: WATERMAN CREEK

096393301, O'Brien, IA

Built 1952 Load: 27.6 t ADT: 30

STARLING AVE

Good

Over: WILLOW CREEK

094 40 16 02 10, O'Brien, IA

Built 2014 Load: 27.9 t ADT: 26

SILVER AVE

Good

Over: WILLOW CREEK

094401902, O'Brien, IA

Built 2017 Load: 27.9 t ADT: 40

480TH ST

Good

Over: WILLOW CREEK

094 40 20 01 10, O'Brien, IA

Built 2018 Load: 27.9 t ADT: 15

SORREL AVE

Good

Over: WILLOW CREEK

094402002, O'Brien, IA

Built 2017 Load: 27.9 t ADT: 30

420TH ST

Good

Over: MCCREATH CREEK

095392101, O'Brien, IA

Built 2015 Load: 27.9 t ADT: 34

OLIVE AVE

Good

Over: MUD CREEK

094420102, O'Brien, IA

Built 2012 Load: 28.2 t ADT: 41

FM

Good

Over: JOHNSON CREEK

095412001, O'Brien, IA

Built 2000 Load: 28.2 t ADT: 50

LOCAL

Good

Over: SO BR LITTLE FLOYD RIVER

096410802, O'Brien, IA

Built 2001 Load: 28.2 t ADT: 46

FM

Good

Over: SMALL UN-NAMED CREEK

097391002, O'Brien, IA

Built 1988 Load: 28.2 t ADT: 509

LOCAL

Good

Over: COLE CREEK

094410202, O'Brien, IA

Built 1998 Load: 28.5 t ADT: 35

FM

Good

Over: SMALL UN-NAMED CREEK

096391001, O'Brien, IA

Built 1998 Load: 28.5 t ADT: 240

330TH ST

Good

Over: SMALL UN-NAMED CREEK

096400101, O'Brien, IA

Built 2004 Load: 28.5 t ADT: 62

LOCAL

Good

Over: SMALL UN-NAMED CREEK

096400102, O'Brien, IA

Built 1991 Load: 28.5 t ADT: 50

SORREL AVE

Good

Over: DRY RUN

096403202, O'Brien, IA

Built 2017 Load: 28.5 t ADT: 21

500TH ST

Good

Over: DOG CREEK

0943934, O'Brien, IA

Built 2009 Load: 29.0 t ADT: 10

LOCAL

Good

Over: WATERMAN CREEK

097391801, O'Brien, IA

Built 1978 Load: 29.2 t ADT: 15

Read our methodology - how this data is sourced, computed, and verified.

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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.