County profile · official public datasets

Teton County, MT

82 public highway bridges tracked in the FHWA National Bridge Inventory: 42.7% rated Good, 54.9% Fair, 2.4% Poor.

82
Public bridges
42.7%
Good condition
2.4%
Poor condition

The verdict

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

Teton County posts a top-quartile lowest Poor-condition share among rated counties in the state across rated county bridge inventory.

Top 14%
lowest Poor share in state
2.4%
Poor-condition share
82
public highway bridges
1975
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.

Teton County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Teton County ranks #8 of 56 Montana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.4%). Teton County, Montana contains 82 public highway bridges. Roughly 42.7% are rated “Good,” 54.9% “Fair,” and 2.4% “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

82

Public highway bridges in Teton County

Good condition

42.7%

35 of 82 rated 7-9

Fair condition

54.9%

45 of 82 rated 5-6

Poor condition

2.4%

2 of 82 rated 4 or below

In-state Poor-share rank

#8 of 56

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

Condition distribution

Share of 82 NBI-tracked bridges by lowest applicable component rating.

Good
42.7% (35)
Fair
54.9% (45)
Poor
2.4% (2)

Teton County's Poor-condition bridges carry 200 vehicle crossings a day

That is 0.7% of the county's reported daily bridge traffic on 2.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 100 crossings a day against 387 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 82 of 82 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

42.7% of Teton County's bridges have passed the 50-year mark

35 of the 82 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 42.7% 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 50% of the county's Poor-condition bridge traffic

8TH LN NE over GREENFIELD SO CANAL 039, built 1966, carries 100 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 2-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 200 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Teton County's bridges were built

82 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1970s, when 25 of the county's bridges still in the inventory were built, which is 30.5% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1975) matches the Montana average (1977).

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

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

The 5 Montana counties nearest Teton County in number of bridges, with their condition splits. Its 2.4% Poor share is the 3rd-lowest of these 6. Its average build year of 1975 against a peer-group mean of 1977 is in line with the group.

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

Bridge inventory size and condition shares for Teton County and the 5 Montana counties closest to it in inventory size
County Bridges Poor
Stillwater County 92 1.1%
Teton County (this page) 82 2.4%
Carbon County 80 5%
Granite County 73 11%
Custer County 71 1.4%
Glacier County 71 5.6%

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

Similar inventory size

Nearest county inventories outside MT (82 bridges here).

Similar average build year

Nearest mean year-built outside MT (1975 here).

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

All 82 Good 35 Fair 45 Poor 2

All bridges (82)

13TH LN NE

Good

Over: MUDDY CREEK 010

2M SW POWER, Teton, MT

Built 2007 Load: 24.5 t ADT: 100

20TH RD NE

Good

Over: SEP I 15 001

4M N DUTTON, Teton, MT

Built 1977 Load: 24.5 t ADT: 100

24TH RD NE

Good

Over: INT COLLINS RD I 15 003

6M SE BRADY, Teton, MT

Built 1977 Load: 24.5 t ADT: 87

I 15

Good

Over: TETON RIVER

6M N DUTTON, Teton, MT

Built 1977 Load: 25.4 t ADT: 1,681

US 89

Good

Over: GREENFIELDS SOUTH CANAL

3M SE FAIRFIELD, Teton, MT

Built 1983 Load: 25.4 t ADT: 1,787

9TH LN NE

Good

Over: MUDDY CREEK 115

4M W POWER, Teton, MT

Built 1982 Load: 26.3 t ADT: 26

2ND LN SE

Good

Over: GREENFIELD CANAL 053

2M SE FAIRFIELD, Teton, MT

Built 1938 Load: 26.3 t ADT: 14

NFSR #144

Good

Over: WEST FORK TETON RIVER

1/2 MI SO OF W.F. STATION, Teton, MT

Built 1977 Load: 27.5 t ADT: 65

COUNTY ROAD 215

Good

Over: TETON RIVER 067

3M NW CHOTEAU, Teton, MT

Built 1976 Load: 28.1 t ADT: 100

US 89

Good

Over: GREENFIELDS MAIN CANAL

1M SE FAIRFIELD, Teton, MT

Built 1983 Load: 29.0 t ADT: 1,787

FDR 109

Good

Over: S FK TETON RIVER

3.5 MI. SW OF JCT 144/109, Teton, MT

Built 1965 Load: 29.8 t ADT: 99

2ND ROAD SW

Good

Over: BIG COULEE

5M SW FAIRFIELD, Teton, MT

Built 2019 Load: 29.9 t ADT: 100

US 89

Good

Over: BIG MUDDY CREEK

BYNUM, Teton, MT

Built 2010 Load: 29.9 t ADT: 570

S 220

Good

Over: MUDDY CREEK

12M N CHOTEAU, Teton, MT

Built 1981 Load: 29.9 t ADT: 383

TETON CANYON RD

Good

Over: BYNUM RESEVOIR CANAL 002

15M W CHOTEAU, Teton, MT

Built 1982 Load: 30.8 t ADT: 154

NFSR 144

Good

Over: NORTH FORK TETON RIVER

W FK STATION, Teton, MT

Built 1977 Load: 31.4 t ADT: 65

COUNTY ROAD 213

Good

Over: SUN RIVER SLOPE CANAL071

3M S PISHKUN RESERVOIR, Teton, MT

Built 2016 Load: 31.8 t ADT: 100

US 89

Good

Over: FOSTER CREEK

1M S BYNUM, Teton, MT

Built 2018 Load: 32.7 t ADT: 579

3RD RD NE

Good

Over: NO NAME DITCH 012

10M NE FAIRFIELD, Teton, MT

Built 1995 Load: 32.7 t ADT: 100

DEEP CREEK RD

Good

Over: DEEP CREEK 065

27M SW CHOTEAU, Teton, MT

Built 1976 Load: 32.7 t ADT: 100

TETON CANYON RD

Good

Over: IRRIGATION CANAL 131

8M W CHOTEAU, Teton, MT

Built 2012 Load: 33.6 t ADT: 172

S DIVISION LN

Good

Over: GREENFIELD CANAL 058

1M S FAIRFIELD, Teton, MT

Built 1978 Load: 36.0 t ADT: 100

I 15

Good

Over: SEP 9TH RD NE

3M N POWER, Teton, MT

Built 1972 Load: 37.2 t ADT: 1,505

I 15

Good

Over: SEP 9TH RD NE

3M N POWER, Teton, MT

Built 1972 Load: 37.2 t ADT: 1,505

BELLVIEW RD

Good

Over: DOG CREEK 062

8M SW CHOTEAU, Teton, MT

Built 2013 Load: 37.2 t ADT: 100

S BELLVIEW RD

Good

Over: DOG CREEK 069

6M SW CHOTEAU, Teton, MT

Built 2013 Load: 37.2 t ADT: 100

S 431

Good

Over: MUDDY CREEK

2M W POWER, Teton, MT

Built 1970 Load: 37.2 t ADT: 503

US 287

Good

Over: USRS CANAL

8M NE AUGUSTA, Teton, MT

Built 2005 Load: 39.9 t ADT: 587

10TH LN NW

Good

Over: MUDDY CREEK 025

12M N CHOTEAU, Teton, MT

Built 2009 Load: 63.5 t ADT: 100

BELLVIEW RD

Good

Over: SEVEN MILE COULEE 130

6M SW CHOTEAU, Teton, MT

Built 1962 Load: 93.4 t ADT: 100

8TH LN NE

Poor

Over: GREENFIELD SO CANAL 039

8M NE FAIRFIELD, Teton, MT

Built 1966 Load: 14.5 t ADT: 100

6TH LN NE

Poor

Over: DRAINAGE 129

13M SW DUTTON, Teton, MT

Built 1974 Load: 18.1 t ADT: 100

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.