County profile · official public datasets

Iron County, MO

126 public highway bridges tracked in the FHWA National Bridge Inventory: 30.2% rated Good, 60.3% Fair, 9.5% Poor.

126
Public bridges
30.2%
Good condition
9.5%
Poor condition

The verdict

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

Iron County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

64th
of 115 on Poor share
9.5%
Poor-condition share
126
public highway bridges
1962
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.

Iron County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Iron County ranks #64 of 115 Missouri counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 9.5%). Iron County, Missouri contains 126 public highway bridges. Roughly 30.2% are rated “Good,” 60.3% “Fair,” and 9.5% “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

126

Public highway bridges in Iron County

Good condition

30.2%

38 of 126 rated 7-9

Fair condition

60.3%

76 of 126 rated 5-6

Poor condition

9.5%

12 of 126 rated 4 or below

In-state Poor-share rank

#64 of 115

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

Condition distribution

Share of 126 NBI-tracked bridges by lowest applicable component rating.

Good
30.2% (38)
Fair
60.3% (76)
Poor
9.5% (12)

Iron County's Poor-condition bridges carry 6,361 vehicle crossings a day

That is 5.6% of the county's reported daily bridge traffic on 9.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 530 crossings a day against 890 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 126 of 126 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

63.5% of Iron County's bridges have passed the 50-year mark

80 of the 126 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 30.2% 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 18.8% of the county's Poor-condition bridge traffic

RT E E over MARBLE CR, built 1936, carries 1,193 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 12-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 6,361 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Iron County's bridges were built

126 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1970s, when 22 of the county's bridges still in the inventory were built, which is 17.5% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1962, 17 years older than the Missouri average of 1979.

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

How Iron County compares with Missouri's closest counties by inventory size

The 5 Missouri counties nearest Iron County in number of bridges, with their condition splits. Its 9.5% Poor share is the 3rd-lowest of these 6. Its average build year of 1962 against a peer-group mean of 1972 is 10 years older.

Showing the 5 closest of 114 Missouri counties eligible for comparison.

Bridge inventory size and condition shares for Iron County and the 5 Missouri counties closest to it in inventory size
County Bridges Poor
Wright County 131 11.5%
Iron County (this page) 126 9.5%
Bollinger County 124 15.3%
Christian County 121 7.4%
Perry County 120 17.5%
Schuyler County 120 3.3%

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

Similar inventory size

Nearest county inventories outside MO (126 bridges here).

Similar average build year

Nearest mean year-built outside MO (1962 here).

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

All 126 Good 38 Fair 76 Poor 12

Good-condition bridges (38)

BARRELL LOTZ RD

Good

Over: BR OF BIG CR

S 16 T 31 N R 3 E, Iron, MO

Built 2004 Load: 9.0 t ADT: 20

COUNTY RD 31

Good

Over: BR OF ST FRANCIS R

S 36 T 35 N R 3 E, Iron, MO

Built 1968 Load: 16.2 t ADT: 300

RIDGE RD-124

Good

Over: CRANE POND CR

S 20 T 32 N R 4 E, Iron, MO

Built 1940 Load: 16.2 t ADT: 45

RT E E

Good

Over: BR MARBLE CR

S 20 T 33 N R 4 E, Iron, MO

Built 1932 Load: 24.3 t ADT: 1,193

RT Z S

Good

Over: COURTOIS CR

S 33 T 35 N R 1 W, Iron, MO

Built 1958 Load: 25.2 t ADT: 106

RT O S

Good

Over: IMBODEN FK

S 22 T 34 N R 2 E, Iron, MO

Built 1957 Load: 26.1 t ADT: 284

RT E E

Good

Over: BR MARBLE CR

S 29 T 33 N R 4 E, Iron, MO

Built 1931 Load: 28.8 t ADT: 1,193

INDUSTRIAL DR

Good

Over: KNOB BR

S 29 T 34 N R 4 E, Iron, MO

Built 1990 Load: 29.7 t ADT: 50

MO 21 S

Good

Over: REEDS CR

S 19 T 35 N R 3 E, Iron, MO

Built 2011 Load: 29.7 t ADT: 2,204

ST MARYS RD

Good

Over: KNOB CR

S 32 T 34 N R 4 E, Iron, MO

Built 1988 Load: 32.4 t ADT: 750

LOWER CARVER 121

Good

Over: LIT CARVER CR

S 34 T 32 N R 3 E, Iron, MO

Built 1972 Load: 32.4 t ADT: 75

RIDGE RD-124

Good

Over: BIG CR

S 14 T 32 N R 3 E, Iron, MO

Built 1995 Load: 32.4 t ADT: 200

MO 21 S

Good

Over: MINOR CR

S 14 T 33 N R 3 E, Iron, MO

Built 1985 Load: 32.4 t ADT: 3,562

CR 53

Good

Over: LOGAN CR

S 9 T 34 N R 3 E, Iron, MO

Built 2023 Load: 32.4 t ADT: 75

RT K E

Good

Over: BEAR BR

S 20 T 31 N R 3 E, Iron, MO

Built 1936 Load: 33.3 t ADT: 306

COUNTY RD 167

Good

Over: BLACK CR

S 8 T 30 N R 4 E, Iron, MO

Built 2012 Load: 34.2 t ADT: 100

COUNTY RD 20

Good

Over: CEDAR CR

S 3 T 34 N R 2 E, Iron, MO

Built 1999 Load: 36.0 t ADT: 100

COUNTY RD 123

Good

Over: BIG CR

S 14 T 32 N R 3 E, Iron, MO

Built 2008 Load: 36.0 t ADT: 250

RT E E

Good

Over: MARBLE CR BR

S 28 T 33 N R 4 E, Iron, MO

Built 1976 Load: 36.9 t ADT: 1,193

RT E E

Good

Over: MARBLE CR

S 23 T 32 N R 4 E, Iron, MO

Built 1978 Load: 36.9 t ADT: 1,193

COUNTY RD 100

Good

Over: STOUTS CR

S 6 T 33 N R 4 E, Iron, MO

Built 2003 Load: 37.8 t ADT: 20

RT BB E

Good

Over: BRUSHY CR

S 1 T 30 N R 3 E, Iron, MO

Built 1962 Load: 37.8 t ADT: 268

UPPER DETMER RD

Good

Over: MARBLE CR

S 34 T 33 N R 4 E, Iron, MO

Built 2017 Load: 40.5 t ADT: 50

RT N N

Good

Over: UP RR

S 12 T 34 N R 3 E, Iron, MO

Built 2007 Load: 42.3 t ADT: 3,309

MO 72 E

Good

Over: STOUTS CR

S 3 T 33 N R 4 E, Iron, MO

Built 2019 Load: 42.3 t ADT: 1,719

MO 72 E

Good

Over: BR OF STOUTS CR

S 36 T 33 N R 4 E, Iron, MO

Built 1930 Load: 42.3 t ADT: 1,719

MO 49 S

Good

Over: BIG CR

S 23 T 31 N R 3 E, Iron, MO

Built 2018 Load: 43.2 t ADT: 1,120

MO 21 S

Good

Over: CARVER CR

S 4 T 32 N R 3 E, Iron, MO

Built 2018 Load: 46.8 t ADT: 876

MORNING SIDE LN

Good

Over: BR OF STROUTS CR

S 25 T 34 N R 3 E, Iron, MO

Built 2019 Load: 46.8 t ADT: 35

MO 72 E

Good

Over: MARTIN BR

S 3 T 33 N R 4 E, Iron, MO

Built 1928 Load: 46.8 t ADT: 1,719

MO 49 S

Good

Over: SUTTON BR

S 36 T 31 N R 3 E, Iron, MO

Built 1924 Load: 49.5 t ADT: 1,120

RT E E

Good

Over: MARBLE CR

S 3 T 32 N R 4 E, Iron, MO

Built 1976 Load: 50.4 t ADT: 1,193

CEMETERY RD

Good

Over: BR OF WILDCAT CR

S 8 T 30 N R 4 E, Iron, MO

Built 2016 Load: 51.3 t ADT: 100

MO 49 S

Good

Over: GOFF BR

S 2 T 32 N R 3 E, Iron, MO

Built 1986 Load: 54.0 t ADT: 1,311

MO 21 S

Good

Over: CLAYBAUGH CR

S 14 T 33 N R 3 E, Iron, MO

Built 1985 Load: 57.6 t ADT: 3,562

RT N S

Good

Over: MILLS CR

S 36 T 34 N R 2 E, Iron, MO

Built 1976 Load: 64.8 t ADT: 1,290

BARRELL LOTZ RD

Good

Over: BR OF BIG CR

S 16 T 31 N R 3 E, Iron, MO

Built 2004 Load: 76.5 t ADT: 30

RT E E

Good

Over: BR MARBLE CR

S 15 T 32 N R 4 E, Iron, MO

Built 1978 Load: 99.0 t ADT: 1,193

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

Related

Browse all → | Rankings →
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.