County profile · official public datasets

Park County, MT

124 public highway bridges tracked in the FHWA National Bridge Inventory: 21% rated Good, 68.5% Fair, 10.5% Poor.

124
Public bridges: 21%
Good condition: 10.5%
Poor condition

The verdict

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

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

46th
of 56 on Poor share: 10.5%
Poor-condition share: 124
public highway bridges: 1976
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.

Park County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Park County ranks #46 of 56 Montana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 10.5%). Park County, Montana contains 124 public highway bridges. Roughly 21% are rated “Good,” 68.5% “Fair,” and 10.5% “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

124

Public highway bridges in Park County

Good condition

21%

26 of 124 rated 7-9

Fair condition

68.5%

85 of 124 rated 5-6

Poor condition

10.5%

13 of 124 rated 4 or below

In-state Poor-share rank

#46 of 56

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

Condition distribution

Share of 124 NBI-tracked bridges by lowest applicable component rating.

Good

21% (26)

Fair

68.5% (85)

Poor

10.5% (13)

Park County's Poor-condition bridges carry 3,915 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 10.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 301 crossings a day against 772 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 124 of 124 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

47.6% of Park County's bridges have passed the 50-year mark

59 of the 124 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 21% 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 72.8% of the county's Poor-condition bridge traffic

US 89 over INT EAST LIVINGSTON I 90, built 1962, carries 2,850 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 13-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 3,915 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

1
1910s

2
1920s

4
1930s

9
1940s

3
1950s

12
1960s

16
1970s

21
1980s

22
1990s

4
2000s

13
2010s

12
2020s

5

What this shows Construction peaked in the 1980s, when 22 of the county's bridges still in the inventory were built, which is 17.7% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1976) matches the Montana average (1977).

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

The 5 Montana counties nearest Park County in number of bridges, with their condition splits. Its 10.5% Poor share is the 5th-lowest of these 6. Its average build year of 1976 against a peer-group mean of 1980 is in line with the group.

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

Bridge inventory size and condition shares for Park County and the 5 Montana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Big Horn County	135	26.7%	68.1%	5.2%	1978
Jefferson County	134	17.9%	76.9%	5.2%	1977
Park County (this page)	124	21%	68.5%	10.5%	1976
Sanders County	120	40%	52.5%	7.5%	1979
Lake County	117	57.3%	27.4%	15.4%	1995
Rosebud County	114	18.4%	76.3%	5.3%	1973

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

Similar inventory size

Nearest county inventories outside MT (124 bridges here).

Bannock County, ID · 124 bridges
Breathitt County, KY · 124 bridges
Caldwell County, LA · 124 bridges
St. Mary County, LA · 124 bridges

Similar average build year

Nearest mean year-built outside MT (1976 here).

Marion County, IN · avg 1976 · 958 bridges
Mohave County, AZ · avg 1976 · 641 bridges
Comanche County, OK · avg 1976 · 593 bridges
Prince George's County, MD · avg 1976 · 576 bridges

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

All 124 Good 26 Fair 85 Poor 13

All bridges (124)

Sort:

Park County Bridge Snapshot

Condition distribution

Park County's Poor-condition bridges carry 3,915 vehicle crossings a day

47.6% of Park County's bridges have passed the 50-year mark

One structure carries 72.8% of the county's Poor-condition bridge traffic

How Park 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

All bridges (124)

I 90

I 90

I 90

DAISY DEAN RD

FIDDLE CREEK RD

ENYART LN

I 90

CONLIN RD

TRAIL CREEK RD

US 89

S 540 - E RIVER RD

I 90

I 90

BUSINESS RTE 90

S 9TH ST-ISLAND DR

W.FK.MILL CREEK RD

FRONTAGE RD E 448

ANDERSON RD

I-90

BIG CREEK RD - NF-

SHIELDS RIVER RD E

US 89

I 90

SIX MILE CREEK RD

S 540-E RIVER RD

I 90

I 90

HYALITE CREEK RD

CINNABAR BASIN RD

NORTH ENTRANCE ROA

CINNABAR BASIN RD

I 90

I 90

TOM MINER CREEK RD

NORTH ENTRANCE ROA

LULU PASS ROAD

Shields River Road

ROAD

MILL CREEK RD.

SIX MILE ROAD

MILL CREEK ROAD

SHIELDS RIVER ROAD

MISSION CREEK ROAD

MILL CREEK RD

I 90

I 90

SHIELDS RIVER ROAD

US 89

BILLY GOAT ROAD

I 90

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