County profile · official public datasets

Miller County, MO

142 public highway bridges tracked in the FHWA National Bridge Inventory: 40.1% rated Good, 49.3% Fair, 10.6% Poor.

142
Public bridges: 40.1%
Good condition: 10.6%
Poor condition

The verdict

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

Miller 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.

74th
of 115 on Poor share: 10.6%
Poor-condition share: 142
public highway bridges: 1971
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.

Miller County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Miller County ranks #74 of 115 Missouri counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 10.6%). Miller County, Missouri contains 142 public highway bridges. Roughly 40.1% are rated “Good,” 49.3% “Fair,” and 10.6% “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

142

Public highway bridges in Miller County

Good condition

40.1%

57 of 142 rated 7-9

Fair condition

49.3%

70 of 142 rated 5-6

Poor condition

10.6%

15 of 142 rated 4 or below

In-state Poor-share rank

#74 of 115

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

Condition distribution

Share of 142 NBI-tracked bridges by lowest applicable component rating.

Good

40.1% (57)

Fair

49.3% (70)

Poor

10.6% (15)

Miller County's Poor-condition bridges carry 3,687 vehicle crossings a day

That is 1.4% of the county's reported daily bridge traffic on 10.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 246 crossings a day against 1,849 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 142 of 142 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

54.9% of Miller County's bridges have passed the 50-year mark

78 of the 142 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 40.1% 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 57.3% of the county's Poor-condition bridge traffic

MO 42 E over SPRING BR, built 1964, carries 2,112 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 15-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 3,687 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

4
1910s

3
1920s

6
1930s

32
1940s

1
1950s

8
1960s

13
1970s

13
1980s

1
1990s

10
2000s

20
2010s

24
2020s

7

What this shows Construction peaked in the 1930s, when 32 of the county's bridges still in the inventory were built, which is 22.5% of those with a recorded year. That cohort is now 85 to 94 years old in the 2024 inventory. Its average build year is 1971, 8 years older than the Missouri average of 1979.

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

The 5 Missouri counties nearest Miller County in number of bridges, with their condition splits. Its 10.6% Poor share is the 3rd-lowest of these 6. Its average build year of 1971 against a peer-group mean of 1974 is in line with the group.

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

Bridge inventory size and condition shares for Miller County and the 5 Missouri counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
McDonald County	145	25.5%	63.4%	11%	1976
Gasconade County	143	32.2%	62.9%	4.9%	1972
Miller County (this page)	142	40.1%	49.3%	10.6%	1971
St. Clair County	139	25.2%	55.4%	19.4%	1972
Ralls County	138	31.9%	60.9%	7.2%	1976
Mercer County	137	44.5%	36.5%	19%	1976

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

Similar inventory size

Nearest county inventories outside MO (142 bridges here).

Monroe County, AL · 142 bridges
Henderson County, IL · 142 bridges
Graham County, KS · 142 bridges
Kenton County, KY · 142 bridges

Similar average build year

Nearest mean year-built outside MO (1971 here).

Wayne County, MI · avg 1971 · 1,026 bridges
Baltimore County, MD · avg 1971 · 783 bridges
Washington County, PA · avg 1971 · 655 bridges
Linn County, OR · avg 1971 · 566 bridges

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

All 142 Good 57 Fair 70 Poor 15

Good-condition bridges (57)

Sort:

Miller County Bridge Snapshot

Condition distribution

Miller County's Poor-condition bridges carry 3,687 vehicle crossings a day

54.9% of Miller County's bridges have passed the 50-year mark

One structure carries 57.3% of the county's Poor-condition bridge traffic

How Miller 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

Good-condition bridges (57)

BURKLE LANE

KLIETHERMES BR RD

BEAR CREEK RD

BEAR CREEK RD

RT OO E

US 54 E

HONEYSUCKLE RD

WITT RD

RT HH S

US 54 E

US 54 W

FOXBERRY RD

SEQUOIA RD

BLUE SPRING DR

OLD ST THOMAS RD

MARTIN RD

ALEXANDER RD

BOECKMAN BRIDGE RD

MADDEN FORD RD

MO 17 S

RT MM S

MO 52 E

MO 17 S

US 54 W

SEQUOIA RD

KLIETHERMES RD

MO 17 S

JENKINS RD

TAYLOR RD

MO 42 E

MO 52 E

RT M E

RABBIT HEAD RD

SPRING GARDEN RD

MO 17 S

MO 17 S

TAVERN CR RD

SOUTH CREEK RD

WATKINS FORD RD

MO 52 E

BEAR CREEK RD

MO 242 W

TAVERN CREEK RD

MO 52 E

BUECHTER RD

CLARK SCHOOL ROAD

MO 17 S

US 54 W

US 54 E

WITT RD

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