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)

FM

Good

Over: FLOYD RIVER

097423002, O'Brien, IA

Built 1989 Load: 38.2 t ADT: 549

WHITE AVE

Good

Over: SEWER CREEK

097393402, O'Brien, IA

Built 2000 Load: 38.3 t ADT: 50

LOCAL SEC RD

Good

Over: LANGE CREEK SOUTH

094422402, O'Brien, IA

Built 2001 Load: 38.5 t ADT: 26

B46 420TH ST

Good

Over: WATERMAN CREEK

095392303, O'Brien, IA

Built 2022 Load: 39.9 t ADT: 26

POLK AVE

Good

Over: MILL CREEK

095411602, O'Brien, IA

Built 2022 Load: 39.9 t ADT: 11

POLK AVE

Good

Over: MILL CREEK

095413302, O'Brien, IA

Built 2021 Load: 39.9 t ADT: 46

340TH ST

Good

Over: WATERMAN CREEK

096390701, O'Brien, IA

Built 2021 Load: 39.9 t ADT: 41

NEST AVE

Good

Over: LAMKIN CREEK

09642090201, O'Brien, IA

Built 2014 Load: 40.0 t ADT: 46

MONROE AVE

Good

Over: FLOYD RIVER OVERFLOW

097422902, O'Brien, IA

Built 2020 Load: 40.5 t ADT: 518

MONROE AVE

Good

Over: IA 60

2.6 mi. S of jct. US 18, O'Brien, IA

Built 2005 Load: 40.8 t ADT: 100

FM

Good

Over: MILL CREEK

094411502, O'Brien, IA

Built 2000 Load: 41.7 t ADT: 828

LOCAL SEC RD

Good

Over: BARRY CREEK

095391701, O'Brien, IA

Built 1976 Load: 41.8 t ADT: 15

FM

Good

Over: LAMKIN CREEK

096422202, O'Brien, IA

Built 1976 Load: 41.8 t ADT: 1,337

LOCAL

Good

Over: ENGELS CREEK

097422202, O'Brien, IA

Built 1981 Load: 41.8 t ADT: 21

LOCAL

Good

Over: SWEENEY CREEK

097423602, O'Brien, IA

Built 1995 Load: 41.9 t ADT: 30

FM

Good

Over: FLOYD RIVER

097421102, O'Brien, IA

Built 2004 Load: 42.5 t ADT: 199

350TH ST

Good

Over: WATERMAN CREEK

Waterman Creek @ 350th St, O'Brien, IA

Built 2017 Load: 42.9 t ADT: 72

TANAGER AVE

Good

Over: WATERMAN CREEK

097401101, O'Brien, IA

Built 2022 Load: 43.4 t ADT: 35

LOCAL

Good

Over: EPPING CREEK

097403602, O'Brien, IA

Built 1985 Load: 43.4 t ADT: 72

FM

Good

Over: WATERMAN CR

094391401, O'Brien, IA

Built 2005 Load: 43.7 t ADT: 45

WILSON AVE

Good

Over: WATERMAN CREEK

94390304, O'Brien, IA

Built 2020 Load: 43.9 t ADT: 21

VAN BUREN AVE

Good

Over: WATERMAN CREEK

97390702, O'Brien, IA

Built 2020 Load: 44.4 t ADT: 15

LOCAL

Good

Over: WOLF CREEK

097421901, O'Brien, IA

Built 1991 Load: 45.0 t ADT: 26

NEST AVE

Good

Over: LITTLE FLOYD RIVER

096420902, O'Brien, IA

Built 2012 Load: 45.4 t ADT: 46

IA 60 SB

Good

Over: US 18

At Jct. U.S. 18, O'Brien, IA

Built 2004 Load: 45.4 t ADT: 1,735

IA 60 NB

Good

Over: U.S. 18

At Jct. U.S. 18, O'Brien, IA

Built 2004 Load: 45.4 t ADT: 1,735

LOCAL

Good

Over: JORDAN CREEK

095393303, O'Brien, IA

Built 1995 Load: 46.3 t ADT: 35

LOCAL

Good

Over: MILL CREEK

096412402, O'Brien, IA

Built 1988 Load: 48.0 t ADT: 15

LOCAL

Good

Over: LITTLE FLOYD RIVER

096420102, O'Brien, IA

Built 1992 Load: 48.0 t ADT: 41

FM

Good

Over: FLOYD RIVER

097410901, O'Brien, IA

Built 2001 Load: 48.2 t ADT: 71

IA 10

Good

Over: MILL CREEK

2.5 mi W of W jct. US 59, O'Brien, IA

Built 1969 Load: 49.2 t ADT: 1,610

FM

Good

Over: MURRAY CREEK

094390808, O'Brien, IA

Built 1987 Load: 49.6 t ADT: 880

ORIOLE AVE

Good

Over: SO BR LITTLE FLOYD RIVER

096410702, O'Brien, IA

Built 1989 Load: 49.9 t ADT: 409

LOCAL

Good

Over: FLOYD RIVER

097421202, O'Brien, IA

Built 1995 Load: 52.6 t ADT: 21

IA 60 SB

Good

Over: FLOYD RIVER

2.5 mi. N of Jct. US 18, O'Brien, IA

Built 2004 Load: 53.9 t ADT: 2,650

IA 60 NB

Good

Over: FLOYD RIVER

2.5 mi N of Jct US 18, O'Brien, IA

Built 2004 Load: 53.9 t ADT: 2,650

FM

Good

Over: MILL CREEK

094413301, O'Brien, IA

Built 2008 Load: 59.0 t ADT: 159

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

Related

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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.