County profile · official public datasets

Dillingham County, AK

3 public highway bridges tracked in the FHWA National Bridge Inventory: 33.3% rated Good, 0% Fair, 66.7% Poor.

3
Public bridges
33.3%
Good condition
66.7%
Poor condition

Dillingham County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Dillingham County, Alaska contains 3 public highway bridges. Roughly 33.3% are rated “Good,” 0% “Fair,” and 66.7% “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.

Dillingham County is too small a bridge inventory (3 bridges) for a reliable Poor-share ordinal against Alaska's other counties, but its bridges make up 0.2% of Alaska's 1,685 total public highway bridges in the FHWA inventory.

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

3

Public highway bridges in Dillingham County

Good condition

33.3%

1 of 3 rated 7-9

Fair condition

0%

0 of 3 rated 5-6

Poor condition

66.7%

2 of 3 rated 4 or below

Condition distribution

Share of 3 NBI-tracked bridges by lowest applicable component rating.

Good
33.3% (1)
Fair
0% (0)
Poor
66.7% (2)

Dillingham County's Poor-condition bridges carry 60 vehicle crossings a day

That is 15% of the county's reported daily bridge traffic on 66.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 30 crossings a day against 340 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 3 of 3 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

0% of Dillingham County's bridges have passed the 50-year mark

0 of the 3 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 33.3% 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 83.3% of the county's Poor-condition bridge traffic

IRR:AIRPORT ROAD over UNNAMED CREEK KOLIGANEK, built 1980, carries 50 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 2-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 60 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Dillingham County's bridges were built

3 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 2 of the county's bridges still in the inventory were built, which is 66.7% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1992) matches the Alaska average (1989).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release
All 3 Good 1 Fair 0 Poor 2

All bridges (3)

IRR:SURAVAK ROAD

Good

Over: WOOD RIVER

ALEKNAGIK, Dillingham, AK

Built 2015 Load: 38.6 t ADT: 340

IRR:AIRPORT ROAD

Poor

Over: UNNAMED CREEK KOLIGANEK

KOLIGANEK, Dillingham, AK

Built 1980 Load: 2.1 t ADT: 50

IRR:KOLGNK DUMP RD

Poor

Over: UNNAMED CREEK

KOLIGANEK, Dillingham, AK

Built 1980 Load: 2.1 t ADT: 10

Read our methodology - how this data is sourced, computed, and verified.

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.