County profile · official public datasets

Cowlitz County, WA

160 public highway bridges tracked in the FHWA National Bridge Inventory: 46.3% rated Good, 50% Fair, 3.8% Poor.

160
Public bridges: 46.3%
Good condition: 3.8%
Poor condition

The verdict

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

Cowlitz County posts a top-quartile lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 23%
lowest Poor share in state: 3.8%
Poor-condition share: 160
public highway bridges: 1974
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.

Cowlitz County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Cowlitz County ranks #9 of 39 Washington counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 3.8%). Cowlitz County, Washington contains 160 public highway bridges. Roughly 46.3% are rated “Good,” 50% “Fair,” and 3.8% “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

160

Public highway bridges in Cowlitz County

Good condition

46.3%

74 of 160 rated 7-9

Fair condition

50%

80 of 160 rated 5-6

Poor condition

3.8%

6 of 160 rated 4 or below

In-state Poor-share rank

#9 of 39

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

Condition distribution

Share of 160 NBI-tracked bridges by lowest applicable component rating.

Good

46.3% (74)

Fair

50% (80)

Poor

3.8% (6)

Cowlitz County's Poor-condition bridges carry 50,342 vehicle crossings a day

That is 3.8% of the county's reported daily bridge traffic on 3.8% of its bridges: Poor-condition structures carry the same share of traffic than their share of the inventory. Each Poor bridge averages 8,390 crossings a day against 7,202 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 160 of 160 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

51.3% of Cowlitz County's bridges have passed the 50-year mark

82 of the 160 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 46.3% 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 67% of the county's Poor-condition bridge traffic

I-5 over LOG DUMP RD & BN RY, built 1972, carries 33,715 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 6-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 50,342 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

4
1930s

4
1940s

4
1950s

25
1960s

31
1970s

38
1980s

13
1990s

19
2000s

12
2010s

5
2020s

5

What this shows Construction peaked in the 1970s, when 38 of the county's bridges still in the inventory were built, which is 23.8% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1974) matches the Washington average (1975).

How Cowlitz County compares with Washington's closest counties by inventory size

The 5 Washington counties nearest Cowlitz County in number of bridges, with their condition splits. Its 3.8% Poor share is the 1st-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1973 is in line with the group.

Showing the 5 closest of 38 Washington counties eligible for comparison.

Bridge inventory size and condition shares for Cowlitz County and the 5 Washington counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Lincoln County	180	56.7%	37.2%	6.1%	1965
Benton County	167	58.7%	35.9%	5.4%	1977
Okanogan County	161	46.6%	45.3%	8.1%	1972
Cowlitz County (this page)	160	46.3%	50%	3.8%	1974
Clallam County	151	56.3%	37.7%	6%	1979
Chelan County	149	57.7%	34.2%	8.1%	1974

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

Similar inventory size

Nearest county inventories outside WA (160 bridges here).

Clay County, KY · 160 bridges
Kittson County, MN · 160 bridges
Rio Arriba County, NM · 160 bridges
Delaware County, OK · 160 bridges

Similar average build year

Nearest mean year-built outside WA (1974 here).

Knox County, TN · avg 1974 · 588 bridges
Summit County, OH · avg 1974 · 563 bridges
Onondaga County, NY · avg 1974 · 472 bridges
Orange County, NY · avg 1974 · 472 bridges

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

All 160 Good 74 Fair 80 Poor 6

All bridges (160)

Sort:

Cowlitz County Bridge Snapshot

Condition distribution

Cowlitz County's Poor-condition bridges carry 50,342 vehicle crossings a day

51.3% of Cowlitz County's bridges have passed the 50-year mark

One structure carries 67% of the county's Poor-condition bridge traffic

How Cowlitz County compares with Washington'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 (160)

ALLENDER RD

ALLENDER RD

CLINE RD

ALLENDER RD

WREN LOOP RD

ABERNATHY CREEK RD

I-5

EAST CC ST

BARNES DR

ROSE VALLEY RD

I-5

OSTRANDER RD

DELAMETER RD

MODROW RD

DELAMETER RD

I-5

SR 504

HOLCOMB RD

OLD PACIFIC HWY N

I-5

I-5

SR 4

W KALAMA RIVER RD

OAK ST

I-5

I-5

SR 433

20TH AVE.

ABERNATHY CREEK RD

SR 4

SOUTH TOUTLE RD

GRADE ST

I-5 N-W RAMP

I-5

SR 4

SR 4

SR 411

WIEST RD

I-5

I-5

I-5

PACIFIC AVE NORTH

CARLON LOOP RD

I-5

SR 432

ALLEN STREET

WEST SIDE HWY

TALLEY WAY

I-5

SR 504

Related