County profile · official public datasets

Columbia County, OR

126 public highway bridges tracked in the FHWA National Bridge Inventory: 32.5% rated Good, 58.7% Fair, 8.7% Poor.

126
Public bridges: 32.5%
Good condition: 8.7%
Poor condition

The verdict

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

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

35th
of 36 on Poor share: 8.7%
Poor-condition share: 126
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.

Columbia County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Columbia County ranks #35 of 36 Oregon counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.7%). Columbia County, Oregon contains 126 public highway bridges. Roughly 32.5% are rated “Good,” 58.7% “Fair,” and 8.7% “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

126

Public highway bridges in Columbia County

Good condition

32.5%

41 of 126 rated 7-9

Fair condition

58.7%

74 of 126 rated 5-6

Poor condition

8.7%

11 of 126 rated 4 or below

In-state Poor-share rank

#35 of 36

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

Condition distribution

Share of 126 NBI-tracked bridges by lowest applicable component rating.

Good

32.5% (41)

Fair

58.7% (74)

Poor

8.7% (11)

Columbia County's Poor-condition bridges carry 18,333 vehicle crossings a day

That is 5.5% of the county's reported daily bridge traffic on 8.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,667 crossings a day against 830 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 126 of 126 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

38.1% of Columbia County's bridges have passed the 50-year mark

48 of the 126 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 32.5% 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 42.6% of the county's Poor-condition bridge traffic

Hwy 92 over Clatskanie River, built 1954, carries 7,806 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 11-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 18,333 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

5
1920s

4
1930s

7
1950s

17
1960s

12
1970s

18
1980s

13
1990s

15
2000s

27
2010s

8

What this shows Construction peaked in the 2000s, when 27 of the county's bridges still in the inventory were built, which is 21.4% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year (1978) matches the Oregon average (1975).

How Columbia County compares with Oregon's closest counties by inventory size

The 5 Oregon counties nearest Columbia County in number of bridges, with their condition splits. Its 8.7% Poor share is the 6th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1977 is in line with the group.

Showing the 5 closest of 35 Oregon counties eligible for comparison.

Bridge inventory size and condition shares for Columbia County and the 5 Oregon counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Yamhill County	149	24.2%	71.1%	4.7%	1975
Wasco County	148	31.8%	60.1%	8.1%	1968
Grant County	144	45.1%	49.3%	5.6%	1980
Harney County	130	54.6%	43.1%	2.3%	1985
Columbia County (this page)	126	32.5%	58.7%	8.7%	1978
Wallowa County	115	53.9%	37.4%	8.7%	1978

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

Similar inventory size

Nearest county inventories outside OR (126 bridges here).

Bibb County, AL · 126 bridges
Coosa County, AL · 126 bridges
Lawrence County, AR · 126 bridges
Coffee County, GA · 126 bridges

Similar average build year

Nearest mean year-built outside OR (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 126 Good 41 Fair 74 Poor 11

Fair-condition bridges (74)

Sort:

Columbia County Bridge Snapshot

Condition distribution

Columbia County's Poor-condition bridges carry 18,333 vehicle crossings a day

38.1% of Columbia County's bridges have passed the 50-year mark

One structure carries 42.6% of the county's Poor-condition bridge traffic

How Columbia County compares with Oregon'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 (74)

BRINN ROAD

SCAPPOOSE-VERNONIA

OR 202 (Hwy 102)

FLACK RD. (CR#722)

US 30 (Hwy 92)

OR 47 (Hwy 102)

BURRIS ROAD

US 30 (Hwy 92)

OLD HWY 30

DUTCH CANYON ROAD

OLD HWY 30

LARSON ROAD

SMITH ROAD

OLD HWY 30

MILTON WAY

PITTSBURG ROAD

OR 202 (Hwy 102)

SCAPPOOSE-VERNONIA

COUNTY RD 3051

CHAPMAN ROAD

CHAPMAN GRANGE RD

BANKSTON RD

OR 47 (Hwy 102)

J P WEST ROAD

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