County profile · official public datasets

Beaverhead County, MT

226 public highway bridges tracked in the FHWA National Bridge Inventory: 23.9% rated Good, 66.8% Fair, 9.3% Poor.

226
Public bridges
23.9%
Good condition
9.3%
Poor condition

The verdict

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

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

42nd
of 56 on Poor share
9.3%
Poor-condition share
226
public highway bridges
1978
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.

Beaverhead County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Beaverhead County ranks #42 of 56 Montana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 9.3%). Beaverhead County, Montana contains 226 public highway bridges. Roughly 23.9% are rated “Good,” 66.8% “Fair,” and 9.3% “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

226

Public highway bridges in Beaverhead County

Good condition

23.9%

54 of 226 rated 7-9

Fair condition

66.8%

151 of 226 rated 5-6

Poor condition

9.3%

21 of 226 rated 4 or below

In-state Poor-share rank

#42 of 56

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

Condition distribution

Share of 226 NBI-tracked bridges by lowest applicable component rating.

Good
23.9% (54)
Fair
66.8% (151)
Poor
9.3% (21)

Beaverhead County's Poor-condition bridges carry 6,044 vehicle crossings a day

That is 3.2% of the county's reported daily bridge traffic on 9.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 288 crossings a day against 406 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 226 of 226 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

46.9% of Beaverhead County's bridges have passed the 50-year mark

106 of the 226 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 23.9% 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 44% of the county's Poor-condition bridge traffic

HWY 91 N over BEAVERHEAD RIVER 033, built 1946, carries 2,660 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 21-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 6,044 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Beaverhead County's bridges were built

226 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 60 of the county's bridges still in the inventory were built, which is 26.5% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1978) matches the Montana average (1977).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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

The 5 Montana counties nearest Beaverhead County in number of bridges, with their condition splits. Its 9.3% Poor share is the 5th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1978 is in line with the group.

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

Bridge inventory size and condition shares for Beaverhead County and the 5 Montana counties closest to it in inventory size
County Bridges Poor
Beaverhead County (this page) 226 9.3%
Gallatin County 210 4.3%
Missoula County 206 7.8%
Flathead County 204 4.9%
Lewis and Clark County 200 5.5%
Lincoln County 190 14.7%

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

Similar inventory size

Nearest county inventories outside MT (226 bridges here).

Similar average build year

Nearest mean year-built outside MT (1978 here).

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

All 226 Good 54 Fair 151 Poor 21

All bridges (226)

FS RTE 192

Good

Over: ROCK CREEK

ROCK CR, Beaverhead, MT

Built 1986 Load: 38.6 t ADT: 40

I 15

Good

Over: SEP COUNTY RD 203

11.2M S MELROSE, Beaverhead, MT

Built 1973 Load: 40.8 t ADT: 1,902

BIMAT LN

Good

Over: RED ROCK RIVER 037

2M N DELL, Beaverhead, MT

Built 2018 Load: 43.5 t ADT: 29

MT-43 FH 20

Good

Over: TRAIL CREEK

17 M W WISDOM, Beaverhead, MT

Built 2021 Load: 45.4 t ADT: 431

MT-43 FH 20

Good

Over: TRAIL CREEK

16 M W WISDOM, Beaverhead, MT

Built 2021 Load: 45.4 t ADT: 431

HWY 91 N

Poor

Over: BIG HOLE RIVER 041

22M N DILLON, Beaverhead, MT

Built 1940 Load: 2.7 t ADT: 155

UPPER N FORK RD

Poor

Over: N FK BIGHOLE RIVER 064

6M NW WISDOM, Beaverhead, MT

Built 1977 Load: 4.5 t ADT: 100

BLACKTAIL RD

Poor

Over: EAST BENCH CANAL 006

2M S DILLON, Beaverhead, MT

Built 1962 Load: 4.5 t ADT: 100

BROWNS BRIDGE RD

Poor

Over: BIG HOLE RIVER 123

6.2M S MELROSE, Beaverhead, MT

Built 1915 Load: 6.4 t ADT: 100

BIG SWAMP CR RD /

Poor

Over: BIG HOLE RIVER 089

5M NW JACKSON, Beaverhead, MT

Built 1925 Load: 7.3 t ADT: 100

RYAN CANYON RD

Poor

Over: BEAVERHEAD RIVER 023

1.2M S BARRETTS INT, Beaverhead, MT

Built 1908 Load: 7.3 t ADT: 14

FDR 7391

Poor

Over: NO DATA ENTERED

NO DATA ENTERED, Beaverhead, MT

Built 1987 Load: 14.6 t ADT: 5

NO DATA ENTERED

Poor

Over: WISE RIVER

SHEEP CR., Beaverhead, MT

Built 1992 Load: 15.2 t ADT: 6

CANYON CR ROAD

Poor

Over: CANYON CR

CANYON CR, Beaverhead, MT

Built 1952 Load: 18.8 t ADT: 50

FDR 606

Poor

Over: BIRCH CR

BIRCH CR, Beaverhead, MT

Built 1954 Load: 21.1 t ADT: 40

NO DATA ENTERED

Poor

Over: WILLOW CR

WILLOW CR, Beaverhead, MT

Built 1954 Load: 21.7 t ADT: 20

RED ROCK RD

Poor

Over: LIMEKILN CANYON 022

7M NW DELL, Beaverhead, MT

Built 1931 Load: 21.8 t ADT: 119

FDR 624

Poor

Over: RUBY CR

RUBY CR, Beaverhead, MT

Built 1952 Load: 22.7 t ADT: 20

STIBAL LN

Poor

Over: RED ROCK RIVER 053

9M NE MONIDA, Beaverhead, MT

Built 1975 Load: 22.7 t ADT: 100

MT HWY 91

Poor

Over: RR

3M SW DILLON, Beaverhead, MT

Built 1936 Load: 22.7 t ADT: 582

BIG SWAMP CR RD

Poor

Over: BIG SWAMP CR

BIG SWAMP CR, Beaverhead, MT

Built 1968 Load: 26.6 t ADT: 15

SWAMP CR ROAD

Poor

Over: BIG SWAMP CR

BIG SWAMP CR, Beaverhead, MT

Built 1968 Load: 26.6 t ADT: 15

MINER LAKE RD

Poor

Over: GOVERNOR CREEK 092

1M SW JACKSON, Beaverhead, MT

Built 1951 Load: 29.0 t ADT: 100

ROCK CREEK RD

Poor

Over: BIG LAKE CREEK 081

4M SW WISDOM, Beaverhead, MT

Built 1958 Load: 32.7 t ADT: 100

HWY 91 N

Poor

Over: BEAVERHEAD RIVER 033

1M N DILLON, Beaverhead, MT

Built 1946 Load: 39.5 t ADT: 2,660

I 15

Poor

Over: INT MONIDA S 509

MONIDA, Beaverhead, MT

Built 1959 Load: 92.5 t ADT: 1,643

Read our methodology - how this data is sourced, computed, and verified.

Related

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.