County profile · official public datasets

Stillwater County, MT

92 public highway bridges tracked in the FHWA National Bridge Inventory: 30.4% rated Good, 68.5% Fair, 1.1% Poor.

92
Public bridges
30.4%
Good condition
1.1%
Poor condition

The verdict

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

Stillwater County posts a top-10% lowest Poor-condition share among rated counties in the state across rated county bridge inventory.

Top 7%
lowest Poor share in state
1.1%
Poor-condition share
92
public highway bridges
1977
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.

Stillwater County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Stillwater County ranks #4 of 56 Montana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 1.1%). Stillwater County, Montana contains 92 public highway bridges. Roughly 30.4% are rated “Good,” 68.5% “Fair,” and 1.1% “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

92

Public highway bridges in Stillwater County

Good condition

30.4%

28 of 92 rated 7-9

Fair condition

68.5%

63 of 92 rated 5-6

Poor condition

1.1%

1 of 92 rated 4 or below

In-state Poor-share rank

#4 of 56

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

Condition distribution

Share of 92 NBI-tracked bridges by lowest applicable component rating.

Good
30.4% (28)
Fair
68.5% (63)
Poor
1.1% (1)

Stillwater County's Poor-condition bridges carry 4,987 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 1.1% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 4,987 crossings a day against 1,660 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 92 of 92 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

58.7% of Stillwater County's bridges have passed the 50-year mark

54 of the 92 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 30.4% 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 100% of the county's Poor-condition bridge traffic

S 78 over YELLOWSTONE RIVER, built 1957, carries 4,987 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 1-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 4,987 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Stillwater County's bridges were built

92 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1970s, when 29 of the county's bridges still in the inventory were built, which is 31.5% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1977) matches the Montana average (1977).

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

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

The 5 Montana counties nearest Stillwater County in number of bridges, with their condition splits. Its 1.1% Poor share is the 1st-lowest of these 6. Its average build year of 1977 against a peer-group mean of 1979 is in line with the group.

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

Bridge inventory size and condition shares for Stillwater County and the 5 Montana counties closest to it in inventory size
County Bridges Poor
Phillips County 101 16.8%
Madison County 97 11.3%
Richland County 97 3.1%
Pondera County 96 4.2%
Sweet Grass County 94 5.3%
Stillwater County (this page) 92 1.1%

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

Similar inventory size

Nearest county inventories outside MT (92 bridges here).

Similar average build year

Nearest mean year-built outside MT (1977 here).

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

All 92 Good 28 Fair 63 Poor 1

Good-condition bridges (28)

JOHNSON BRIDGE RD

Good

Over: STILLWATER RIVER

2M NW ABSAROKEE, Stillwater, MT

Built 2021 Load: 17.2 t ADT: 66

I 90

Good

Over: SEP YOUNGS POINT ROAD

4.3M W PARK CITY, Stillwater, MT

Built 1970 Load: 22.7 t ADT: 5,470

GROVE CREEK RD

Good

Over: FISHTAIL CREEK 038

1M NW FISHTAIL, Stillwater, MT

Built 2004 Load: 22.7 t ADT: 100

STILLWATER RIV RD

Good

Over: STILLWATER RIVER 026

10M SW ABSAROKEE, Stillwater, MT

Built 2009 Load: 22.7 t ADT: 100

STILLWATER RIV RD

Good

Over: W FORK STILLWATER RIVER

1M N NYE, Stillwater, MT

Built 2003 Load: 24.5 t ADT: 721

STILLWATER RIV RD

Good

Over: W FORK STILLWATER RIVER

1M N NYE, Stillwater, MT

Built 2003 Load: 24.5 t ADT: 721

NYE RD-S 419

Good

Over: W ROSEBUD CREEK OVERFLOW

FISHTAIL, Stillwater, MT

Built 1991 Load: 25.4 t ADT: 1,544

SLEEPY HOLLOW RD

Good

Over: W ROSEBUD CREEK 032

11M SW ABSAROKEE, Stillwater, MT

Built 2004 Load: 27.2 t ADT: 100

S 78

Good

Over: BUTCHER CREEK

2M S ABSAROKEE, Stillwater, MT

Built 2010 Load: 29.0 t ADT: 1,887

INGERSOLL CREEK RO

Good

Over: W ROSEBUD CREEK

10M SW ABSAROKEE, Stillwater, MT

Built 2019 Load: 29.9 t ADT: 100

CENTENNIAL RD

Good

Over: KEYSER CREEK 043

NW EDGE COLUMBUS, Stillwater, MT

Built 2005 Load: 30.8 t ADT: 100

OLD US 10

Good

Over: BIG DITCH 017

6M W PARK CITY, Stillwater, MT

Built 1955 Load: 32.4 t ADT: 1,607

I 90

Good

Over: BERRY CREEK

7.4M E REED POINT, Stillwater, MT

Built 1963 Load: 32.7 t ADT: 5,353

VALLEY CREEK RD

Good

Over: VALLEY CREEK 009

6M NW PARK CITY, Stillwater, MT

Built 2008 Load: 32.7 t ADT: 100

COUNTRYMAN CR RD

Good

Over: COUNTRYMAN CREEK 050

6M SW COLUMBUS, Stillwater, MT

Built 1996 Load: 32.7 t ADT: 100

W FORK RD

Good

Over: LIMESTONE CREEK 051

3M NW NYE, Stillwater, MT

Built 2004 Load: 32.7 t ADT: 100

W ROSEBUD RD

Good

Over: W ROSEBUD CREEK 033

12M SW ABSAROKEE, Stillwater, MT

Built 2004 Load: 32.7 t ADT: 100

NYE RD-S 419

Good

Over: FISHTAIL CREEK

3M SW FISHTAIL, Stillwater, MT

Built 1994 Load: 32.7 t ADT: 1,055

N STILLWATER RD

Good

Over: STILLWATER RIVER 021

2M NE ABSAROKEE, Stillwater, MT

Built 2001 Load: 33.6 t ADT: 100

ROSEBUD CEMETERY R

Good

Over: BUTCHER CREEK 030

3M S ABSAROKEE, Stillwater, MT

Built 2013 Load: 35.4 t ADT: 100

S 78

Good

Over: JOE HILL CREEK

4M SW COLUMBUS, Stillwater, MT

Built 2007 Load: 35.4 t ADT: 2,305

I 90

Good

Over: INT REED POINT

REED POINT, Stillwater, MT

Built 1963 Load: 36.3 t ADT: 5,353

S 78

Good

Over: BEAVER CREEK

2M NE ABSAROKEE, Stillwater, MT

Built 2010 Load: 38.1 t ADT: 2,305

W ROSEBUD RD

Good

Over: W ROSEBUD CREEK 034

14M SW ABSAROKEE, Stillwater, MT

Built 2017 Load: 39.0 t ADT: 100

I 90

Good

Over: BERRY CREEK

7.4M E REED POINT, Stillwater, MT

Built 1971 Load: 40.8 t ADT: 5,353

SPRING CREEK RD

Good

Over: STILLWATER RIVER 036

7M W ABSAROKEE, Stillwater, MT

Built 2018 Load: 41.7 t ADT: 100

W GROVE ST

Good

Over: ROSEBUD CREEK

ABSAROKEE-W GROVE ST, Stillwater, MT

Built 1989 Load: 44.5 t ADT: 504

I 90

Good

Over: COVE IRRIGATION DITCH

6.2M W PARK CITY, Stillwater, MT

Built 1970 Load: 99.9 t ADT: 10,939

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

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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.