County profile · official public datasets

Dawson County, MT

109 public highway bridges tracked in the FHWA National Bridge Inventory: 8.3% rated Good, 85.3% Fair, 6.4% Poor.

109
Public bridges: 8.3%
Good condition: 6.4%
Poor condition

The verdict

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

Dawson 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.

32nd
of 56 on Poor share: 6.4%
Poor-condition share: 109
public highway bridges: 1972
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.

Dawson County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Dawson County ranks #32 of 56 Montana counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.4%). Dawson County, Montana contains 109 public highway bridges. Roughly 8.3% are rated “Good,” 85.3% “Fair,” and 6.4% “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

109

Public highway bridges in Dawson County

Good condition

8.3%

9 of 109 rated 7-9

Fair condition

85.3%

93 of 109 rated 5-6

Poor condition

6.4%

7 of 109 rated 4 or below

In-state Poor-share rank

#32 of 56

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

Condition distribution

Share of 109 NBI-tracked bridges by lowest applicable component rating.

Good

8.3% (9)

Fair

85.3% (93)

Poor

6.4% (7)

Dawson County's Poor-condition bridges carry 4,698 vehicle crossings a day

That is 3.2% of the county's reported daily bridge traffic on 6.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 671 crossings a day against 313 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 109 of 109 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

57.8% of Dawson County's bridges have passed the 50-year mark

63 of the 109 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 8.3% 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 91% of the county's Poor-condition bridge traffic

I 94 over CLEAR CREEK, built 1973, carries 4,277 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 7-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 4,698 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

3
1930s

2
1940s

1
1950s

11
1960s

36
1970s

29
1980s

17
1990s

3
2000s

4
2010s

2
2020s

1

What this shows Construction peaked in the 1960s, when 36 of the county's bridges still in the inventory were built, which is 33% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1972, 5 years older than the Montana average of 1977.

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

The 5 Montana counties nearest Dawson County in number of bridges, with their condition splits. Its 6.4% Poor share is the 3rd-lowest of these 6. Its average build year of 1972 against a peer-group mean of 1979 is 7 years older.

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

Bridge inventory size and condition shares for Dawson County and the 5 Montana counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Lake County	117	57.3%	27.4%	15.4%	1995
Rosebud County	114	18.4%	76.3%	5.3%	1973
Powell County	113	25.7%	68.1%	6.2%	1981
Dawson County (this page)	109	8.3%	85.3%	6.4%	1972
Valley County	104	10.6%	76.9%	12.5%	1975
Blaine County	102	33.3%	56.9%	9.8%	1969

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

Similar inventory size

Nearest county inventories outside MT (109 bridges here).

Mariposa County, CA · 109 bridges
Boone County, IL · 109 bridges
Gove County, KS · 109 bridges
Hodgeman County, KS · 109 bridges

Similar average build year

Nearest mean year-built outside MT (1972 here).

Santa Clara County, CA · avg 1972 · 964 bridges
Madison County, AL · avg 1972 · 710 bridges
Kern County, CA · avg 1972 · 668 bridges
York County, PA · avg 1972 · 569 bridges

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

All 109 Good 9 Fair 93 Poor 7

Fair-condition bridges (93)

Sort:

Dawson County Bridge Snapshot

Condition distribution

Dawson County's Poor-condition bridges carry 4,698 vehicle crossings a day

57.8% of Dawson County's bridges have passed the 50-year mark

One structure carries 91% of the county's Poor-condition bridge traffic

How Dawson 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 (93)

COUNTY ROAD 544

ROAD 244

ROAD 229

ROAD 261

JEFFERSON SCHL RD

COUNTY ROAD 526

COUNTY ROAD 532

ROAD 261

ROAD 255

I 94

ROAD 261

I 94

I 94

ROAD 217

S 200

SEVEN MILE DR

WHOOPUP RD-RD 248

S 254

I 94

I 94

FRONTAGE ROAD 315

S 200S-TOWNE ST

S 200S-TOWNE ST

I 94

PLEASANT VIEW RD

S 200S-TOWNE ST

US 94

US 94

MARSH RD

S 16

I 94

I 94

I 94

I 94

I 94

S 16

I 94

I 94

I 94

I 94

I 94

I 94

BAD ROUTE RD

DRY CREEK ROAD

I 94

I 94

S 200

S 254

I 94

ROAD 223

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