Total bridges
26
Public highway bridges in Treasure County
County profile · official public datasets
Treasure County, MT
26 public highway bridges tracked in the FHWA National Bridge Inventory: 34.6% rated Good, 50% Fair, 15.4% Poor.
- 26
- Public bridges
- 34.6%
- Good condition
- 15.4%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Treasure County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.
- 54th
- of 56 on Poor share
- 15.4%
- Poor-condition share
- 26
- public highway bridges
- 1966
- 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.
Treasure County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Treasure County ranks #54 of 56 Montana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 15.4%). Treasure County, Montana contains 26 public highway bridges. Roughly 34.6% are rated “Good,” 50% “Fair,” and 15.4% “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.
Good condition
34.6%
9 of 26 rated 7-9
Fair condition
50%
13 of 26 rated 5-6
Poor condition
15.4%
4 of 26 rated 4 or below
In-state Poor-share rank
#54 of 56
Among Montana counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 26 NBI-tracked bridges by lowest applicable component rating.
Good 34.6% (9)
Fair 50% (13)
Poor 15.4% (4)
Treasure County's Poor-condition bridges carry 542 vehicle crossings a day
That is 3.2% of the county's reported daily bridge traffic on 16% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 136 crossings a day against 1,666 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 25 of 26 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
61.5% of Treasure County's bridges have passed the 50-year mark
16 of the 26 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 34.6% 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 51.5% of the county's Poor-condition bridge traffic
FRONTAGE ROAD 018 over IRRIGATION DITCH 001, built 1933, carries 279 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 4-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 542 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Treasure County's bridges were built
26 bridges with a recorded construction year, grouped by decade
- 1920s 1
1920–1929
1 bridges
- 1930s
1930–1939
5 bridges
- 1950s 1
1950–1959
1 bridges
- 1960s
1960–1969
5 bridges
- 1970s
1970–1979
10 bridges
- 1980s 1
1980–1989
1 bridges
- 1990s 1
1990–1999
1 bridges
- 2010s 2
2010–2019
2 bridges
What this shows Construction peaked in the 1970s, when 10 of the county's bridges still in the inventory were built, which is 38.5% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1966, 11 years older than the Montana average of 1977.
How Treasure County compares with Montana's closest counties by inventory size
The 5 Montana counties nearest Treasure County in number of bridges, with their condition splits. Its 15.4% Poor share is the 6th-lowest of these 6. Its average build year of 1966 against a peer-group mean of 1977 is 11 years older.
Showing the 5 closest of 55 Montana counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Musselshell County | 28 | 57.1% | 39.3% | 3.6% | 1986 |
| Garfield County | 26 | 38.5% | 57.7% | 3.8% | 1989 |
| Petroleum County | 26 | 30.8% | 53.8% | 15.4% | 1967 |
| Wheatland County | 26 | 30.8% | 61.5% | 7.7% | 1967 |
| Treasure County (this page) | 26 | 34.6% | 50% | 15.4% | 1966 |
| Wibaux County | 25 | 12% | 84% | 4% | 1975 |
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 Treasure 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 Treasure County, both outside Montana so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside MT (26 bridges here).
- Mineral County, CO · 26 bridges
- Webster County, GA · 26 bridges
- St. James County, LA · 26 bridges
- Deaf Smith County, TX · 26 bridges
Similar average build year
Nearest mean year-built outside MT (1966 here).
- Butler County, KS · avg 1966 · 591 bridges
- Grafton County, NH · avg 1966 · 544 bridges
- Queens County, NY · avg 1966 · 514 bridges
- Lehigh County, PA · avg 1966 · 381 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Good-condition bridges (9)
TULLOCK RD
GoodOver: INT BIGHORN I 94 002
1M S BIGHORN, Treasure, MT
Built 1963 Load: 20.0 t ADT: 100
I 94
GoodOver: SARPY CREEK
18.6M E BIGHORN, Treasure, MT
Built 1976 Load: 21.8 t ADT: 2,067
I 94
GoodOver: INT HYSHAM
14.9M E BIGHORN, Treasure, MT
Built 1976 Load: 24.5 t ADT: 2,489
MISSION VALLEY RD
GoodOver: FROZE TO DEATH CR 013
2M NW MYERS, Treasure, MT
Built 1986 Load: 27.2 t ADT: 9
I 94
GoodOver: SARPY CREEK
18.6M E BIGHORN, Treasure, MT
Built 1967 Load: 28.1 t ADT: 2,489
OLD HWY 10
GoodOver: SARPY CREEK 014
5M E HYSHAM, Treasure, MT
Built 2015 Load: 29.0 t ADT: 218
MEYERS RD
GoodOver: ALKALI CREEK
4M NW MYERS, Treasure, MT
Built 1977 Load: 29.9 t ADT: 95
I 94
GoodOver: INT HYSHAM
14.9M E BIGHORN, Treasure, MT
Built 1964 Load: 30.8 t ADT: 2,554
I 94
GoodOver: SEP RR
18.6M E BIGHORN, Treasure, MT
Built 1973 Load: 99.9 t ADT: 4,977
Read our methodology - how this data is sourced, computed, and verified.
Related
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.