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.

1920s

19
1930s

21
1940s

8
1950s

11
1960s

12
1970s

22
1980s

10
1990s

7
2000s

7
2010s

8
2020s

1

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.

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	Good	Fair	Poor	Avg. built
Wright County	131	21.4%	67.2%	11.5%	1964
Iron County (this page)	126	30.2%	60.3%	9.5%	1962
Bollinger County	124	30.6%	54%	15.3%	1962
Christian County	121	41.3%	51.2%	7.4%	1978
Perry County	120	27.5%	55%	17.5%	1965
Schuyler County	120	65.8%	30.8%	3.3%	1989

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).

Bibb County, AL · 126 bridges
Coosa County, AL · 126 bridges
Lawrence County, AR · 126 bridges
Coffee County, GA · 126 bridges

Similar average build year

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

Berks County, PA · avg 1962 · 667 bridges
Pecos County, TX · avg 1962 · 470 bridges
Bristol County, MA · avg 1962 · 384 bridges
Norfolk County, MA · avg 1962 · 343 bridges

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

All bridges (126)

Sort:

Iron County Bridge Snapshot

Condition distribution

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

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

One structure carries 18.8% of the county's Poor-condition bridge traffic

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

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (126)

MULBERRY ST

LEONARD HUFF -137

RT C E

ADAMS CR RD

MO 49 S

E MADISON ST

RT E E

COUNTY RD 96

COUNTY RD 020

SUTTON HOLLOW -147

COUNTY RD 157

OLD RTE 21

BUFFORD BOTTOM

COUNTY RD 79

FLAT WOODS RD

BEAVER SLIDE RD

MINIMUN RD

COUNTY RD 149

OLD HWY 21

HARRY BAYS-001

RT A S

RT A S

MO 32 E

MO 143 S

RT A S

RT E E

RT K E

BANNER RD

COUNTY RD 119

DESARC TURNOFF-167

MO 32 E

RT O S

MO 221 S

MO 21 S

ADAM CREEK RD

RT N S

MO 221 S

MO 49 S

MO 72 E

RT E E

MO 32 E

RT O S

RT Z S

MO 49 S

COUNTY RD 42

MO 49 S

MO 32 E

MO 49 S

RT BB E

MO 49 S

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