County profile · official public datasets

Yukon-Koyukuk County, AK

94 public highway bridges tracked in the FHWA National Bridge Inventory: 41.5% rated Good, 50% Fair, 8.5% Poor.

94
Public bridges: 41.5%
Good condition: 8.5%
Poor condition

The verdict

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

Yukon-Koyukuk 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.

20th
of 27 on Poor share: 8.5%
Poor-condition share: 94
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.

Yukon-Koyukuk County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Yukon-Koyukuk County ranks #20 of 27 Alaska counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.5%). Yukon-Koyukuk County, Alaska contains 94 public highway bridges. Roughly 41.5% are rated “Good,” 50% “Fair,” and 8.5% “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 Yukon-Koyukuk County

Good condition

41.5%

39 of 94 rated 7-9

Fair condition

50%

47 of 94 rated 5-6

Poor condition

8.5%

8 of 94 rated 4 or below

In-state Poor-share rank

#20 of 27

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

Condition distribution

Share of 94 NBI-tracked bridges by lowest applicable component rating.

Good

41.5% (39)

Fair

50% (47)

Poor

8.5% (8)

Yukon-Koyukuk County's Poor-condition bridges carry 462 vehicle crossings a day

That is 1.9% of the county's reported daily bridge traffic on 8.5% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 58 crossings a day against 185 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 94 of 94 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

58.5% of Yukon-Koyukuk County's bridges have passed the 50-year mark

55 of the 94 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 41.5% 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 23.8% of the county's Poor-condition bridge traffic

IRR:STEESE HIGHWAY over CROOKED CREEK, built 1957, carries 110 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 8-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 462 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1930s

3
1940s

3
1950s

8
1960s

10
1970s

38
1980s

8
1990s

4
2000s

10
2010s

9
2020s

1

What this shows Construction peaked in the 1970s, when 38 of the county's bridges still in the inventory were built, which is 40.4% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1978, 11 years older than the Alaska average of 1989.

How Yukon-Koyukuk County compares with Alaska's closest counties by inventory size

The 5 Alaska counties nearest Yukon-Koyukuk County in number of bridges, with their condition splits. Its 8.5% Poor share is the 4th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1989 is 11 years older.

Showing the 5 closest of 26 Alaska counties eligible for comparison.

Bridge inventory size and condition shares for Yukon-Koyukuk County and the 5 Alaska counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Matanuska-Susitna County	120	50.8%	43.3%	5.8%	1993
Fairbanks North Star County	111	50.5%	42.3%	7.2%	1988
Kenai Peninsula County	103	35.9%	50.5%	13.6%	1988
Ketchikan Gateway County	100	43%	45%	12%	1993
Yukon-Koyukuk County (this page)	94	41.5%	50%	8.5%	1978
Chugach County	66	39.4%	53%	7.6%	1983

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 Yukon-Koyukuk 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 Yukon-Koyukuk County, both outside Alaska so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside AK (94 bridges here).

Lee County, AR · 94 bridges
Huerfano County, CO · 94 bridges
Henry County, KY · 94 bridges
Pendleton County, KY · 94 bridges

Similar average build year

Nearest mean year-built outside AK (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 94 Good 39 Fair 47 Poor 8

Fair-condition bridges (47)

Sort:

Yukon-Koyukuk County Bridge Snapshot

Condition distribution

Yukon-Koyukuk County's Poor-condition bridges carry 462 vehicle crossings a day

58.5% of Yukon-Koyukuk County's bridges have passed the 50-year mark

One structure carries 23.8% of the county's Poor-condition bridge traffic

How Yukon-Koyukuk County compares with Alaska'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 (47)

DALTON HIGHWAY

TOTCHAKET ROAD

TOTCHAKET ROAD

TOTCHAKET ROAD

STERLING L/OPHIR

STERLING L/OPHIR

STERLING L/OPHIR

DENALI PARK ROAD

DENALI PARK ROAD

WISEMAN ROAD

DENALI PARK ROAD

IRR:STEESE HIGHWAY

DENALI PARK ROAD

DENALI PARK ROAD

DENALI PARK ROAD

STERLING L/OPHIR

ELLIOTT HIGHWAY

DENALI PARK ROAD

PARKS HIGHWAY

PARKS HIGHWAY

PARKS HIGHWAY

STEESE HIGHWAY

STEESE HIGHWAY

STEESE HIGHWAY

ELLIOTT HIGHWAY

STEESE HIGHWAY

IRR:AIRPORT ROAD

DENALI PARK ROAD

DALTON HIGHWAY

DENALI PARK ROAD

DENALI PARK ROAD

CIRCLE HOT SPRINGS

IRR: VILLAGE ROAD

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

DALTON HIGHWAY

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