County profile · official public datasets

Flathead County, MT

204 public highway bridges tracked in the FHWA National Bridge Inventory: 30.9% rated Good, 64.2% Fair, 4.9% Poor.

204
Public bridges: 30.9%
Good condition: 4.9%
Poor condition

The verdict

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

Flathead County pairs a better-than-median Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

Top 34%
lowest Poor share in state: 4.9%
Poor-condition share: 204
public highway bridges: 1983
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.

Flathead County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Flathead County ranks #19 of 56 Montana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.9%). Flathead County, Montana contains 204 public highway bridges. Roughly 30.9% are rated “Good,” 64.2% “Fair,” and 4.9% “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

204

Public highway bridges in Flathead County

Good condition

30.9%

63 of 204 rated 7-9

Fair condition

64.2%

131 of 204 rated 5-6

Poor condition

4.9%

10 of 204 rated 4 or below

In-state Poor-share rank

#19 of 56

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

Condition distribution

Share of 204 NBI-tracked bridges by lowest applicable component rating.

Good

30.9% (63)

Fair

64.2% (131)

Poor

4.9% (10)

Flathead County's Poor-condition bridges carry 13,131 vehicle crossings a day

That is 2.9% of the county's reported daily bridge traffic on 4.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,313 crossings a day against 2,597 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 204 of 204 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

32.8% of Flathead County's bridges have passed the 50-year mark

67 of the 204 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 30.9% 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 62.1% of the county's Poor-condition bridge traffic

S 82 over FLATHEAD RIVER, built 1955, carries 8,155 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 10-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 13,131 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

1
1920s

3
1930s

8
1950s

11
1960s

35
1970s

24
1980s

38
1990s

30
2000s

32
2010s

21
2020s

1

What this shows Construction peaked in the 1980s, when 38 of the county's bridges still in the inventory were built, which is 18.6% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1983, 6 years newer than the Montana average of 1977.

How Flathead County compares with Montana's closest counties by inventory size

The 5 Montana counties nearest Flathead County in number of bridges, with their condition splits. Its 4.9% Poor share is the 3rd-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1975 is 8 years newer.

Showing the 5 closest of 55 Montana counties eligible for comparison.

Bridge inventory size and condition shares for Flathead County and the 5 Montana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Gallatin County	210	19%	76.7%	4.3%	1977
Missoula County	206	33.5%	58.7%	7.8%	1976
Flathead County (this page)	204	30.9%	64.2%	4.9%	1983
Lewis and Clark County	200	58%	36.5%	5.5%	1979
Lincoln County	190	38.4%	46.8%	14.7%	1977
Cascade County	185	41.6%	54.6%	3.8%	1965

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

Similar inventory size

Nearest county inventories outside MT (204 bridges here).

Greene County, AL · 204 bridges
Pembina County, ND · 204 bridges
Okfuskee County, OK · 204 bridges
Robertson County, TN · 204 bridges

Similar average build year

Nearest mean year-built outside MT (1983 here).

Dallas County, TX · avg 1983 · 3,230 bridges
Bexar County, TX · avg 1983 · 2,342 bridges
Sedgwick County, KS · avg 1983 · 1,333 bridges
Will County, IL · avg 1983 · 649 bridges

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

All 204 Good 63 Fair 131 Poor 10

Good-condition bridges (63)

Sort:

Flathead County Bridge Snapshot

Condition distribution

Flathead County's Poor-condition bridges carry 13,131 vehicle crossings a day

32.8% of Flathead County's bridges have passed the 50-year mark

One structure carries 62.1% of the county's Poor-condition bridge traffic

How Flathead County compares with Montana'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 (63)

FORST ROAD

Forest Road

FOREST ROAD

NFSR

LOWER VALLEY RD

TETRAULT RD

BROWNS MEADOW RD

DEMERSVILLE RD

FOREST ROAD

S 556-THOMPSON R R

FOREST ROAD

NFSR

ROSE CROSSING

NORTH FORK RD

INSIDE NORTH FORK

FOREST ROAD

BIRCH GROVE W

S 40

FOREST ROAD

WHALEBONE DR

HODGSON RD

FOREST ROAD

FOREST ROAD

US 93 BYPASS

CANYON CR ROAD

NORTH FORK RD

FOREST ROAD

NO DATA ENTERED

SOMERS STAGE RD

FOREST ROAD

FOREST ROAD

TWO MILE DRIVE

FOREST ROAD

FOREST ROAD

NORTH FORK RD

US 93 BYPASS

INSIDE NORTH FORK

INSIDE NORTH FORK

BAKER AVE

FOREST ROAD

NFSR

FOREST ROAD

NORTH FORK RD

N00109

FOREST ROAD

FOUR MILE DRIVE

WOLF CREEK DR

US 2

US 93 ALTERNATE

FOREST ROAD

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