County profile · official public datasets

Glacier County, MT

71 public highway bridges tracked in the FHWA National Bridge Inventory: 38% rated Good, 56.3% Fair, 5.6% Poor.

71
Public bridges: 38%
Good condition: 5.6%
Poor condition

The verdict

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

Glacier County posts a better-than-median Poor-condition share among rated counties in the state across rated county bridge inventory.

Top 50%
lowest Poor share in state: 5.6%
Poor-condition share: 71
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.

Glacier County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Glacier County ranks #28 of 56 Montana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 5.6%). Glacier County, Montana contains 71 public highway bridges. Roughly 38% are rated “Good,” 56.3% “Fair,” and 5.6% “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

Public highway bridges in Glacier County

Good condition

38%

27 of 71 rated 7-9

Fair condition

56.3%

40 of 71 rated 5-6

Poor condition

5.6%

4 of 71 rated 4 or below

In-state Poor-share rank

#28 of 56

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

Condition distribution

Share of 71 NBI-tracked bridges by lowest applicable component rating.

Good

38% (27)

Fair

56.3% (40)

Poor

5.6% (4)

Glacier County's Poor-condition bridges carry 310 vehicle crossings a day

That is 0.5% of the county's reported daily bridge traffic on 5.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 78 crossings a day against 730 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 71 of 71 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

50.7% of Glacier County's bridges have passed the 50-year mark

36 of the 71 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 38% 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 32.3% of the county's Poor-condition bridge traffic

IRR BIA RTE 2 over DAWSON CREEK, built 1932, 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 4-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 310 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

1
1930s

6
1940s

1
1950s

7
1960s

16
1970s

9
1980s

5
1990s

6
2000s

11
2010s

8
2020s

1

What this shows Construction peaked in the 1960s, when 16 of the county's bridges still in the inventory were built, which is 22.5% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1978) matches the Montana average (1977).

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

The 5 Montana counties nearest Glacier County in number of bridges, with their condition splits. Its 5.6% Poor share is the 4th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1974 is in line with the group.

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

Bridge inventory size and condition shares for Glacier County and the 5 Montana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Granite County	73	37%	52.1%	11%	1974
Custer County	71	14.1%	84.5%	1.4%	1969
Glacier County (this page)	71	38%	56.3%	5.6%	1978
Deer Lodge County	68	27.9%	66.2%	5.9%	1973
Silver Bow County	68	16.2%	82.4%	1.5%	1974
Sheridan County	66	16.7%	80.3%	3%	1979

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

Similar inventory size

Nearest county inventories outside MT (71 bridges here).

Rio Grande County, CO · 71 bridges
Charlton County, GA · 71 bridges
Madison County, GA · 71 bridges
Taylor County, GA · 71 bridges

Similar average build year

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

Orange County, CA · avg 1978 · 1,164 bridges
Sumner County, KS · avg 1978 · 659 bridges
Allen County, IN · avg 1978 · 613 bridges
Livingston County, IL · avg 1978 · 579 bridges

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

All 71 Good 27 Fair 40 Poor 4

Fair-condition bridges (40)

Sort:

Glacier County Bridge Snapshot

Condition distribution

Glacier County's Poor-condition bridges carry 310 vehicle crossings a day

50.7% of Glacier County's bridges have passed the 50-year mark

One structure carries 32.3% of the county's Poor-condition bridge traffic

How Glacier 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

Fair-condition bridges (40)

IRR - US 89

GUNSIGHT RD

NPS SERVICE ROAD

MANY GLACIER ROAD

CHIEF MOUNTAIN INT

GOING-TO-THE-SUN R

GOING-TO-THE-SUN R

US 89

DUCK LAKE RD

IRR BIA RTE 1

IRR BIA RTE 25

IRR RTE BIA 55

IRR - US 2

TWO MEDICINE ROAD

GOING-TO-THE-SUN R

IRR BIA RTE 4

TWO MEDICINE ROAD

IRR BIA RTE 1

IRR BIA RTE 1

IRR BIA RTE 2

IRR BIA RTE 130

IRR BIA RTE 130

IRR BIA RTE 57

IRR BIA RTE 8

RISING SUN CAMPGRO

SULLIVAN BRIDGE RD

IRR - S 49

IRR - US 89

S 213

DUCK LAKE RD

IRR - US 89

IRR - US 2

IRR BIA RTE 10

IRR BIA RTE 10

IRR - US 2

IRR - US 2

IRR - US 89

IRR BIA RTE 25

IRR - US 2

US 2

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