Total bridges
264
Public highway bridges in O'Brien County
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.
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
- 1900s 8
1900–1909
8 bridges
- 1910s 4
1910–1919
4 bridges
- 1920s 9
1920–1929
9 bridges
- 1930s
1930–1939
20 bridges
- 1940s 9
1940–1949
9 bridges
- 1950s
1950–1959
30 bridges
- 1960s
1960–1969
26 bridges
- 1970s
1970–1979
26 bridges
- 1980s
1980–1989
27 bridges
- 1990s
1990–1999
24 bridges
- 2000s
2000–2009
40 bridges
- 2010s
2010–2019
29 bridges
- 2020s 12
2020–2029
12 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).
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.
| 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 (this page) | 264 | 51.9% | 43.2% | 4.9% | 1976 |
| Guthrie County | 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 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).
- Pueblo County, CO · 264 bridges
- Wise County, TX · 264 bridges
- Chatham County, GA · 265 bridges
- Rock County, MN · 265 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 (114)
MONROE AVE
FairOver: DEEP CREEK
094422902, O'Brien, IA
Built 2007 Load: 22.0 t ADT: 11
LOCAL SEC RD
FairOver: NELSON CR
094412601, O'Brien, IA
Built 1935 Load: 22.4 t ADT: 30
LOCAL SEC RD
FairOver: LANGE CREEK
094422306, O'Brien, IA
Built 1954 Load: 22.4 t ADT: 62
LOCAL SEC RD
FairOver: WATERMAN CREEK
095392701, O'Brien, IA
Built 1951 Load: 22.4 t ADT: 26
FM
FairOver: FLOYD RIVER
097422902, O'Brien, IA
Built 1962 Load: 22.4 t ADT: 518
FM
FairOver: WATERMAN CREEK
094390314, O'Brien, IA
Built 1961 Load: 22.5 t ADT: 210
LOCAL SEC RD
FairOver: MUD CREEK
094420202, O'Brien, IA
Built 1934 Load: 22.7 t ADT: 103
LOCAL
FairOver: LAKE CREEK
095400901, O'Brien, IA
Built 1992 Load: 22.7 t ADT: 21
LOCAL
FairOver: LAKE CREEK
095400902, O'Brien, IA
Built 2006 Load: 22.7 t ADT: 30
LOCAL
FairOver: SWEENEY CREEK
096 42 02 01, O'Brien, IA
Built 2013 Load: 22.7 t ADT: 50
LOCAL
FairOver: FLOYD RIVER OVERFLOW
097421502, O'Brien, IA
Built 1933 Load: 22.7 t ADT: 26
LOCAL
FairOver: MUD CREEK
094410502, O'Brien, IA
Built 1950 Load: 23.3 t ADT: 72
LOCAL
FairOver: WATERMAN CREEK
096392901, O'Brien, IA
Built 1952 Load: 23.3 t ADT: 30
LOCAL
FairOver: FLOYD RIVER
097410702, O'Brien, IA
Built 1939 Load: 23.7 t ADT: 26
LOCAL
FairOver: W BR MILL CREEK
096413201, O'Brien, IA
Built 1947 Load: 24.0 t ADT: 30
LOCAL
FairOver: MILL CREEK
094412901, O'Brien, IA
Built 1970 Load: 24.9 t ADT: 46
LOCAL
FairOver: LAKE CREEK
095400801, O'Brien, IA
Built 1979 Load: 24.9 t ADT: 26
US 59
FairOver: BRANCH FLOYD RIVER
1.9 mi. N of N jct. US 18, O'Brien, IA
Built 1976 Load: 25.1 t ADT: 1,320
LOCAL
FairOver: W BR MILL CREEK
096413301, O'Brien, IA
Built 1928 Load: 25.3 t ADT: 15
FM
FairOver: SMALL UN-NAMED CREEK
097391202, O'Brien, IA
Built 1935 Load: 25.3 t ADT: 34
FM
FairOver: HENRY CREEK
094392405, O'Brien, IA
Built 1950 Load: 25.9 t ADT: 45
LOCAL
FairOver: WILLOW CR
094412501, O'Brien, IA
Built 1978 Load: 26.6 t ADT: 11
FM
FairOver: FLOYD RIVER
097411001, O'Brien, IA
Built 1969 Load: 26.6 t ADT: 45
FM
FairOver: LITTLE FLOYD RIVER
097413102, O'Brien, IA
Built 1968 Load: 26.6 t ADT: 409
US 59
FairOver: MILL CREEK
4.2 mi. N of N Jct IA 10, O'Brien, IA
Built 1973 Load: 27.7 t ADT: 940
FM
FairOver: NO FOLK FLOYD RIVER
097410901, O'Brien, IA
Built 1994 Load: 28.2 t ADT: 71
FM
FairOver: W BRANCH MILL CREEK
095410401, O'Brien, IA
Built 1959 Load: 28.5 t ADT: 1,087
FM
FairOver: MILL CREEK BRANCH
095410401, O'Brien, IA
Built 1959 Load: 28.8 t ADT: 1,087
FM
FairOver: MILL CREEK
095410401, O'Brien, IA
Built 1984 Load: 29.0 t ADT: 1,087
US 18
FairOver: LITTLE FLOYD RIVER
0.1 mi W of E jct SR L40, O'Brien, IA
Built 1957 Load: 29.1 t ADT: 4,230
FM
FairOver: DRY RUN
095412702, O'Brien, IA
Built 1961 Load: 30.4 t ADT: 917
FM
FairOver: LITTLE FLOYD RIVER
096420610, O'Brien, IA
Built 1963 Load: 30.4 t ADT: 609
FM
FairOver: MUD CREEK
094411701, O'Brien, IA
Built 1968 Load: 30.6 t ADT: 71
LOCAL SEC RD
FairOver: BARRY CREEK
095392102, O'Brien, IA
Built 1900 Load: 32.4 t ADT: 41
LOCAL
FairOver: SMALL UN-NAMED CREEK
094403102, O'Brien, IA
Built 1974 Load: 32.7 t ADT: 62
LOCAL
FairOver: SMALL UN-NAMED CREEK
094403202, O'Brien, IA
Built 1973 Load: 32.7 t ADT: 35
LOCAL
FairOver: W BR WHISKEY CREEK
094413102, O'Brien, IA
Built 1978 Load: 32.7 t ADT: 21
LOCAL
FairOver: BARRY CREEK
095392801, O'Brien, IA
Built 1980 Load: 32.7 t ADT: 41
LOCAL
FairOver: MCCREATH CREEK
095392801, O'Brien, IA
Built 1980 Load: 32.7 t ADT: 41
FM
FairOver: STOFFERAN CREEK
095420301, O'Brien, IA
Built 1971 Load: 32.7 t ADT: 968
FM
FairOver: WILLOW CREEK
095420801, O'Brien, IA
Built 1972 Load: 32.7 t ADT: 828
LOCAL SEC RD
FairOver: GRASS WATERWAY
095421701, O'Brien, IA
Built 1900 Load: 32.7 t ADT: 26
LOCAL
FairOver: WILLOW CREEK
096392501, O'Brien, IA
Built 1900 Load: 32.7 t ADT: 11
FM
FairOver: LITTLE WATERMAN CREEK
096402301, O'Brien, IA
Built 1955 Load: 32.7 t ADT: 300
FM
FairOver: WATERMAN CREEK
097401101, O'Brien, IA
Built 2004 Load: 32.7 t ADT: 30
FM
FairOver: ENGELS CREEK
097422302, O'Brien, IA
Built 1925 Load: 32.7 t ADT: 199
ORIOLE AVE
FairOver: GRASS WATERWAY
096410702, O'Brien, IA
Built 1965 Load: 32.7 t ADT: 409
US 18
FairOver: STREAM
1.6 mi. W of jct. SR M12, O'Brien, IA
Built 1958 Load: 32.7 t ADT: 3,530
FM
FairOver: MUD CREEK
094420302, O'Brien, IA
Built 2002 Load: 34.0 t ADT: 878
FM
FairOver: MILL CREEK
095413402, O'Brien, IA
Built 1961 Load: 34.0 t ADT: 917
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.