County profile · official public datasets

Harrison County, MO

331 public highway bridges tracked in the FHWA National Bridge Inventory: 39.6% rated Good, 39% Fair, 21.5% Poor.

331
Public bridges: 39.6%
Good condition: 21.5%
Poor condition

The verdict

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

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

113th
of 115 on Poor share: 21.5%
Poor-condition share: 331
public highway bridges: 1981
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.

Harrison County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Harrison County ranks #113 of 115 Missouri counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 21.5%). Harrison County, Missouri contains 331 public highway bridges. Roughly 39.6% are rated “Good,” 39% “Fair,” and 21.5% “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

331

Public highway bridges in Harrison County

Good condition

39.6%

131 of 331 rated 7-9

Fair condition

39%

129 of 331 rated 5-6

Poor condition

21.5%

71 of 331 rated 4 or below

In-state Poor-share rank

#113 of 115

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

Condition distribution

Share of 331 NBI-tracked bridges by lowest applicable component rating.

Good

39.6% (131)

Fair

39% (129)

Poor

21.5% (71)

Harrison County's Poor-condition bridges carry 13,141 vehicle crossings a day

That is 6.8% of the county's reported daily bridge traffic on 21.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 185 crossings a day against 151 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 331 of 331 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

38.7% of Harrison County's bridges have passed the 50-year mark

128 of the 331 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 39.6% 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 37.3% of the county's Poor-condition bridge traffic

US 136 E over IS 35, built 1973, carries 4,896 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 71-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 13,141 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

5
1920s

17
1930s

28
1940s

6
1950s

14
1960s

37
1970s

30
1980s

19
1990s

60
2000s

63
2010s

43
2020s

9

What this shows Construction peaked in the 2000s, when 63 of the county's bridges still in the inventory were built, which is 19% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year (1981) matches the Missouri average (1979).

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

The 5 Missouri counties nearest Harrison County in number of bridges, with their condition splits. Its 21.5% Poor share is the 6th-lowest of these 6. Its average build year of 1981 against a peer-group mean of 1983 is in line with the group.

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

Bridge inventory size and condition shares for Harrison County and the 5 Missouri counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Boone County	334	49.4%	46.7%	3.9%	1984
Franklin County	331	38.7%	56.8%	4.5%	1988
Harrison County (this page)	331	39.6%	39%	21.5%	1981
Bates County	319	22.6%	70.2%	7.2%	1977
Audrain County	314	41.4%	53.8%	4.8%	1987
Linn County	313	39%	43.5%	17.6%	1980

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

Similar inventory size

Nearest county inventories outside MO (331 bridges here).

Sebastian County, AR · 331 bridges
Pike County, KY · 331 bridges
Hickman County, TN · 331 bridges
Bowie County, TX · 331 bridges

Similar average build year

Nearest mean year-built outside MO (1981 here).

Franklin County, OH · avg 1981 · 922 bridges
Greenville County, SC · avg 1981 · 635 bridges
Montgomery County, OH · avg 1981 · 632 bridges
McLean County, IL · avg 1981 · 624 bridges

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

All 331 Good 131 Fair 129 Poor 71

All bridges (331)

Sort:

Harrison County Bridge Snapshot

Condition distribution

Harrison County's Poor-condition bridges carry 13,141 vehicle crossings a day

38.7% of Harrison County's bridges have passed the 50-year mark

One structure carries 37.3% of the county's Poor-condition bridge traffic

How Harrison 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 (331)

RT T S

RT M E

RT UU E

W 395 ST

W 150 AVE

RT B S

RT H E

RT W S

RT V S

RT ZZ S

IS 35 S

IS 35 N

IS 35 S

IS 35 N

IS 35 S

W 150 ST

RT N E

E 340TH STREET

IS 35 N

IS 35 N

E 190 ST

RT A E

MO 13 S

IS 35 S

15TH ST

12TH ST

W 160 ST

W 160 ST

E 280 AVE

W 211 LN

E 290 AVE

W 300 ST

RT EE S

W 385 ST

RT CC N

W 375 ST

RT HH E

E 110 ST

E 345 ST

W 150 AVE

E 400 ST

E 185 ST

190TH ST

RT H E

MO 146 E

RT A E

E 280 AVE

W 117 ST

E 330 AVE

W 267 ST

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