County profile · official public datasets

Linn County, MO

313 public highway bridges tracked in the FHWA National Bridge Inventory: 39% rated Good, 43.5% Fair, 17.6% Poor.

313
Public bridges: 39%
Good condition: 17.6%
Poor condition

The verdict

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

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

104th
of 115 on Poor share: 17.6%
Poor-condition share: 313
public highway bridges: 1980
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.

Linn County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Linn County ranks #104 of 115 Missouri counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 17.6%). Linn County, Missouri contains 313 public highway bridges. Roughly 39% are rated “Good,” 43.5% “Fair,” and 17.6% “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

313

Public highway bridges in Linn County

Good condition

39%

122 of 313 rated 7-9

Fair condition

43.5%

136 of 313 rated 5-6

Poor condition

17.6%

55 of 313 rated 4 or below

In-state Poor-share rank

#104 of 115

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

Condition distribution

Share of 313 NBI-tracked bridges by lowest applicable component rating.

Good

39% (122)

Fair

43.5% (136)

Poor

17.6% (55)

Linn County's Poor-condition bridges carry 22,110 vehicle crossings a day

That is 8.7% of the county's reported daily bridge traffic on 17.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 402 crossings a day against 273 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 313 of 313 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

34.8% of Linn County's bridges have passed the 50-year mark

109 of the 313 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 39% 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 39.5% of the county's Poor-condition bridge traffic

US 36 E over SIGHTS BR, built 1924, carries 8,727 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 55-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 22,110 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

2
1910s

1
1920s

8
1930s

26
1940s

21
1950s

26
1960s

20
1970s

14
1980s

30
1990s

76
2000s

60
2010s

24
2020s

5

What this shows Construction peaked in the 1990s, when 76 of the county's bridges still in the inventory were built, which is 24.3% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1980) matches the Missouri average (1979).

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

The 5 Missouri counties nearest Linn County in number of bridges, with their condition splits. Its 17.6% Poor share is the 6th-lowest of these 6. Its average build year of 1980 against a peer-group mean of 1982 is in line with the group.

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

Bridge inventory size and condition shares for Linn County and the 5 Missouri counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Bates County	319	22.6%	70.2%	7.2%	1977
Audrain County	314	41.4%	53.8%	4.8%	1987
Linn County (this page)	313	39%	43.5%	17.6%	1980
Callaway County	303	39.3%	54.5%	6.3%	1978
Adair County	301	60.8%	32.6%	6.6%	1992
Newton County	300	39%	54.3%	6.7%	1978

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

Similar inventory size

Nearest county inventories outside MO (313 bridges here).

Natchitoches County, LA · 313 bridges
Cedar County, NE · 313 bridges
Jackson County, AL · 314 bridges
Cloud County, KS · 314 bridges

Similar average build year

Nearest mean year-built outside MO (1980 here).

Tulsa County, OK · avg 1980 · 1,135 bridges
Miami-Dade County, FL · avg 1980 · 1,057 bridges
Pulaski County, AR · avg 1980 · 721 bridges
McLennan County, TX · avg 1980 · 714 bridges

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

All 313 Good 122 Fair 136 Poor 55

Good-condition bridges (122)

Sort:

Linn County Bridge Snapshot

Condition distribution

Linn County's Poor-condition bridges carry 22,110 vehicle crossings a day

34.8% of Linn County's bridges have passed the 50-year mark

One structure carries 39.5% of the county's Poor-condition bridge traffic

How Linn 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 (122)

AUSTIN RD

IDAHO RD

ARGO RD

HYDE RD

BOW DR

JASMINE RD

NOBLE RD

DEXTER RD

IRA DR

INGEL RD

MO 139 S

RT C E

RT WW E

JASPER RD

DELCO RD

RT V S

MO 5 S

ELK RD

AMES RD

LAMB DR

KAYAK RD

NOEL DR

ARBOR RD

INCA RD

AMES RD

HUSK RD

KEMPER DR

CALICO RD

MAPLE DR

HARDIN RD

KIOWA RD

ARTIC RD

CALICO RD

DEXTER RD

EAGLE RD

GETTY RD

GAS RD

RT M S

INCA RD

MARTONS RD

CLARK DR

ARMOR RD

BEECH RD

BELT RD

EMPIRE DR

FORT DR

DELCO RD

LOCK DR

AFTON RD

AUTO RD

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