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.

1900s

1
1930s

4
1940s

8
1950s

22
1960s

27
1970s

9
1980s

19
1990s

10
2000s

19
2010s

7
2020s

4

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).

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	Good	Fair	Poor	Avg. built
Muscatine County	144	34.7%	43.8%	21.5%	1979
Hancock County	138	39.9%	39.9%	20.3%	1981
Boone County	135	27.4%	43%	29.6%	1955
Palo Alto County	135	23%	58.5%	18.5%	1973
Monroe County (this page)	130	26.2%	49.2%	24.6%	1977
Worth County	116	35.3%	48.3%	16.4%	1970

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).

Kit Carson County, CO · 130 bridges
Bay County, FL · 130 bridges
Lowndes County, GA · 130 bridges
Whitfield County, GA · 130 bridges

Similar average build year

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

San Diego County, CA · avg 1977 · 1,632 bridges
King County, WA · avg 1977 · 1,238 bridges
Riverside County, CA · avg 1977 · 1,117 bridges
Shelby County, TN · avg 1977 · 1,077 bridges

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

Fair-condition bridges (64)

Sort:

Monroe County Bridge Snapshot

Condition distribution

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

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

One structure carries 36% of the county's Poor-condition bridge traffic

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

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (64)

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