County profile · official public datasets

Monroe County, IA

130 public highway bridges tracked in the FHWA National Bridge Inventory: 26.2% rated Good, 49.2% Fair, 24.6% Poor.

130
Public bridges
26.2%
Good condition
24.6%
Poor condition

The verdict

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

Monroe County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

67th
of 99 on Poor share
24.6%
Poor-condition share
130
public highway bridges
1977
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.

Monroe County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Monroe County ranks #67 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 24.6%). Monroe County, Iowa contains 130 public highway bridges. Roughly 26.2% are rated “Good,” 49.2% “Fair,” and 24.6% “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

130

Public highway bridges in Monroe County

Good condition

26.2%

34 of 130 rated 7-9

Fair condition

49.2%

64 of 130 rated 5-6

Poor condition

24.6%

32 of 130 rated 4 or below

In-state Poor-share rank

#67 of 99

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

Condition distribution

Share of 130 NBI-tracked bridges by lowest applicable component rating.

Good
26.2% (34)
Fair
49.2% (64)
Poor
24.6% (32)

Monroe County's Poor-condition bridges carry 4,397 vehicle crossings a day

That is 9.5% of the county's reported daily bridge traffic on 24.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 137 crossings a day against 323 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 130 of 130 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

51.5% of Monroe County's bridges have passed the 50-year mark

67 of the 130 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 26.2% 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 36% of the county's Poor-condition bridge traffic

SOUTH CLINTON ST over OVER BNSF RR, built 1932, carries 1,585 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 32-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 4,397 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Monroe County's bridges were built

130 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1960s, when 27 of the county's bridges still in the inventory were built, which is 20.8% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1977) matches the Iowa average (1979).

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

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

The 5 Iowa counties nearest Monroe County in number of bridges, with their condition splits. Its 24.6% Poor share is the 5th-lowest of these 6. Its average build year of 1977 against a peer-group mean of 1972 is 5 years newer.

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

Bridge inventory size and condition shares for Monroe County and the 5 Iowa counties closest to it in inventory size
County Bridges Poor
Muscatine County 144 21.5%
Hancock County 138 20.3%
Boone County 135 29.6%
Palo Alto County 135 18.5%
Monroe County (this page) 130 24.6%
Worth County 116 16.4%

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

Similar inventory size

Nearest county inventories outside IA (130 bridges here).

Similar average build year

Nearest mean year-built outside IA (1977 here).

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

All 130 Good 34 Fair 64 Poor 32

All bridges (130)

LOCAL

Poor

Over: DRAINAGE

071172907, Monroe, IA

Built 1943 Load: 0.0 t ADT: 40

LOCAL

Poor

Over: CREEK

071192406, Monroe, IA

Built 1939 Load: 5.4 t ADT: 34

FM

Poor

Over: GRAYS CREEK

073172402, Monroe, IA

Built 1951 Load: 7.2 t ADT: 45

LOCAL

Poor

Over: DRAINAGE

073192507, Monroe, IA

Built 1952 Load: 7.2 t ADT: 50

FM

Poor

Over: LOCAL CREEK

071163103, Monroe, IA

Built 1958 Load: 9.1 t ADT: 110

FM

Poor

Over: STREAM

073160306, Monroe, IA

Built 1958 Load: 9.1 t ADT: 25

LOCAL

Poor

Over: CREEK

071191502, Monroe, IA

Built 1959 Load: 10.3 t ADT: 30

LOCAL

Poor

Over: DRAINAGE

073171906, Monroe, IA

Built 1948 Load: 11.2 t ADT: 20

LOCAL

Poor

Over: DRAINAGE

073161506, Monroe, IA

Built 1956 Load: 11.6 t ADT: 20

LOCAL

Poor

Over: CREEK

071193204, Monroe, IA

Built 1959 Load: 12.4 t ADT: 40

FM

Poor

Over: STREAM

071181303, Monroe, IA

Built 1942 Load: 12.6 t ADT: 80

FM

Poor

Over: BNSF RR

072160701, Monroe, IA

Built 1936 Load: 13.9 t ADT: 360

LOCAL

Poor

Over: CREEK

071192003, Monroe, IA

Built 1970 Load: 14.6 t ADT: 40

FM

Poor

Over: OVER UP RR

072171203, Monroe, IA

Built 1936 Load: 15.1 t ADT: 360

FM

Poor

Over: STREAM

071180203, Monroe, IA

Built 1940 Load: 15.2 t ADT: 70

LOCAL

Poor

Over: DRAINAGE

071181008, Monroe, IA

Built 1965 Load: 15.8 t ADT: 20

LOCAL

Poor

Over: DRAINAGE

072173305, Monroe, IA

Built 1968 Load: 16.0 t ADT: 110

FM

Poor

Over: GREYS CREEK

073172208, Monroe, IA

Built 1965 Load: 16.6 t ADT: 60

720TH AVE

Poor

Over: STREAM

073163404, Monroe, IA

Built 1965 Load: 17.0 t ADT: 45

FM

Poor

Over: STREAM

073170803, Monroe, IA

Built 1951 Load: 18.0 t ADT: 70

LOCAL T-35

Poor

Over: CREEK

071172504, Monroe, IA

Built 1950 Load: 18.2 t ADT: 60

FM

Poor

Over: AVERY CREEK

071161103, Monroe, IA

Built 1970 Load: 19.5 t ADT: 80

LOCAL

Poor

Over: DRAINAGE

073191302, Monroe, IA

Built 1996 Load: 19.5 t ADT: 11

LOCAL

Poor

Over: DRAINAGE

073191301, Monroe, IA

Built 1997 Load: 19.9 t ADT: 45

LOCAL

Poor

Over: DRAINAGE DITCH

071161403, Monroe, IA

Built 1974 Load: 20.0 t ADT: 11

LOCAL

Poor

Over: AVERY CREEK

071160904, Monroe, IA

Built 1967 Load: 21.2 t ADT: 26

LOCAL

Poor

Over: DRAINAGE

072172503, Monroe, IA

Built 1941 Load: 23.0 t ADT: 20

FM

Poor

Over: AVERY CREEK

071160203, Monroe, IA

Built 1958 Load: 24.3 t ADT: 80

FM

Poor

Over: CREEK

072170703, Monroe, IA

Built 1963 Load: 24.8 t ADT: 310

TRALEE ST S.

Poor

Over: CEDAR CREEK

071190406, Monroe, IA

Built 1977 Load: 30.2 t ADT: 520

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.