County profile · official public datasets

Mills County, IA

184 public highway bridges tracked in the FHWA National Bridge Inventory: 29.3% rated Good, 51.6% Fair, 19% Poor.

184
Public bridges
29.3%
Good condition
19%
Poor condition

The verdict

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

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

50th
of 99 on Poor share
19%
Poor-condition share
184
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.

Mills County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Mills County ranks #50 of 99 Iowa counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 19%). Mills County, Iowa contains 184 public highway bridges. Roughly 29.3% are rated “Good,” 51.6% “Fair,” and 19% “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

184

Public highway bridges in Mills County

Good condition

29.3%

54 of 184 rated 7-9

Fair condition

51.6%

95 of 184 rated 5-6

Poor condition

19%

35 of 184 rated 4 or below

In-state Poor-share rank

#50 of 99

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

Condition distribution

Share of 184 NBI-tracked bridges by lowest applicable component rating.

Good
29.3% (54)
Fair
51.6% (95)
Poor
19% (35)

Mills County's Poor-condition bridges carry 4,868 vehicle crossings a day

That is 1.7% of the county's reported daily bridge traffic on 19% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 139 crossings a day against 2,557 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 184 of 184 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

56% of Mills County's bridges have passed the 50-year mark

103 of the 184 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 29.3% 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 31.3% of the county's Poor-condition bridge traffic

FA-BARRUS RD over PONY CREEK, built 1969, carries 1,524 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 35-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 4,868 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Mills County's bridges were built

184 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1960s, when 42 of the county's bridges still in the inventory were built, which is 22.8% of those with a recorded year. That cohort is now 55 to 64 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 Mills County compares with Iowa's closest counties by inventory size

The 5 Iowa counties nearest Mills County in number of bridges, with their condition splits. Its 19% Poor share is the 3rd-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1975 is in line with the group.

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

Bridge inventory size and condition shares for Mills County and the 5 Iowa counties closest to it in inventory size
County Bridges Poor
Adams County 186 44.6%
Osceola County 185 8.6%
Mills County (this page) 184 19%
Appanoose County 183 31.1%
Keokuk County 183 19.7%
Ida County 182 16.5%

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

Similar inventory size

Nearest county inventories outside IA (184 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 184 Good 54 Fair 95 Poor 35

All bridges (184)

LCL-COMPASS AVE

Poor

Over: FARM CREEK

073401407, Mills, IA

Built 1963 Load: 0.0 t ADT: 5

LCL-MARH AVE

Poor

Over: NISHNA RIVER

071410201, Mills, IA

Built 1940 Load: 4.0 t ADT: 40

LCL-JARRED AVE

Poor

Over: CREEK

072402405, Mills, IA

Built 1940 Load: 6.0 t ADT: 15

LCL-ELLINGTON

Poor

Over: KEG CREEK

073423103, Mills, IA

Built 1964 Load: 6.3 t ADT: 41

LCL-QUIGG AVE

Poor

Over: SPRING VALLEY CR

071422605, Mills, IA

Built 1940 Load: 6.9 t ADT: 11

LCL-QUEEN AVE

Poor

Over: DEER CREEK

071403003, Mills, IA

Built 1940 Load: 7.2 t ADT: 15

LCL-PATHFIELD

Poor

Over: WAUBONSIE CR

071421803, Mills, IA

Built 1940 Load: 7.4 t ADT: 20

LCL-FRY AVE

Poor

Over: MUD CREEK

073413605, Mills, IA

Built 1940 Load: 7.5 t ADT: 26

LCL-400TH ST

Poor

Over: INDIAN CREEK

072401102, Mills, IA

Built 1940 Load: 8.0 t ADT: 26

LCL-400TH ST

Poor

Over: HUNTERS BRANCH

071402602, Mills, IA

Built 1965 Load: 8.3 t ADT: 26

LCL-INGRAHAM AV

Poor

Over: STREAM

072401501, Mills, IA

Built 1954 Load: 9.8 t ADT: 5

LCL-ELDERBERRY

Poor

Over: MUD CREEK

073412505, Mills, IA

Built 1960 Load: 10.0 t ADT: 60

LCL-RAINS AV

Poor

Over: HUNTER BRANCH

071403401, Mills, IA

Built 1950 Load: 11.7 t ADT: 15

FM-PADDOCK RD

Poor

Over: LOCAL CREEK

071432103, Mills, IA

Built 1970 Load: 12.4 t ADT: 71

LCL-380TH ST

Poor

Over: DEER CREEK

071400904, Mills, IA

Built 1977 Load: 12.6 t ADT: 5

LCL-RIST AVE

Poor

Over: DRAINAGE

071433403, Mills, IA

Built 1961 Load: 14.1 t ADT: 15

LCL-PAINTER RD

Poor

Over: DRAINAGE

071432708, Mills, IA

Built 1930 Load: 14.9 t ADT: 35

LCL-380TH ST

Poor

Over: INDIAN CREEK

072402108, Mills, IA

Built 1964 Load: 14.9 t ADT: 50

LCL-400TH ST

Poor

Over: INDIAN CREEK

072402602, Mills, IA

Built 1957 Load: 15.1 t ADT: 50

FM-397TH ST

Poor

Over: FARM CREEK

073401504, Mills, IA

Built 1959 Load: 18.1 t ADT: 34

FM-215TH ST

Poor

Over: CREEK

071431004, Mills, IA

Built 1969 Load: 20.3 t ADT: 91

FA-PADDOCK AVE

Poor

Over: HUNTERS BRANCH

071402301, Mills, IA

Built 1962 Load: 22.7 t ADT: 51

FA-GASTON AVE

Poor

Over: DRAINAGE

072410605, Mills, IA

Built 1951 Load: 24.3 t ADT: 139

FA-BARRUS RD

Poor

Over: KEG CREEK

073420839, Mills, IA

Built 1951 Load: 25.9 t ADT: 698

LCL-MERRILL RD

Poor

Over: DRAINAGE

071410104, Mills, IA

Built 1964 Load: 26.7 t ADT: 50

LCL-ALLIS RD

Poor

Over: STREAM

073441304, Mills, IA

Built 1978 Load: 29.0 t ADT: 89

FA-GASTON AVE

Poor

Over: KEG CREEK

072420603, Mills, IA

Built 1967 Load: 31.1 t ADT: 1,065

310TH ST

Poor

Over: STREAM

071413202, Mills, IA

Built 1960 Load: 31.4 t ADT: 325

LCL-410TH ST

Poor

Over: INDIAN CREEK

072402604, Mills, IA

Built 1950 Load: 32.2 t ADT: 51

LCL-RAINS AVE

Poor

Over: SPRING VALLEY CREEK

071423601, Mills, IA

Built 1970 Load: 32.7 t ADT: 20

LCL-410TH ST

Poor

Over: LOCAL CREEK

072403606, Mills, IA

Built 1972 Load: 32.7 t ADT: 51

LCL-JESUP AVE

Poor

Over: MAJOR DRAINAGE

072432003, Mills, IA

Built 1970 Load: 32.7 t ADT: 133

FA-BARRUS RD

Poor

Over: PONY CREEK

073431401, Mills, IA

Built 1969 Load: 32.7 t ADT: 1,524

LCL-305TH ST

Poor

Over: CREEK

072411804, Mills, IA

Built 1990 Load: 34.7 t ADT: 11

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.