Total bridges
100
Public highway bridges in Ketchikan Gateway County
County profile · official public datasets
Ketchikan Gateway County, AK
100 public highway bridges tracked in the FHWA National Bridge Inventory: 43% rated Good, 45% Fair, 12% Poor.
- 100
- Public bridges
- 43%
- Good condition
- 12%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Ketchikan Gateway County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- 22nd
- of 27 on Poor share
- 12%
- Poor-condition share
- 100
- public highway bridges
- 1993
- 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.
Ketchikan Gateway County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Ketchikan Gateway County ranks #22 of 27 Alaska counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 12%). Ketchikan Gateway County, Alaska contains 100 public highway bridges. Roughly 43% are rated “Good,” 45% “Fair,” and 12% “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.
Good condition
43%
43 of 100 rated 7-9
Fair condition
45%
45 of 100 rated 5-6
Poor condition
12%
12 of 100 rated 4 or below
In-state Poor-share rank
#22 of 27
Among Alaska counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 100 NBI-tracked bridges by lowest applicable component rating.
Good 43% (43)
Fair 45% (45)
Poor 12% (12)
Ketchikan Gateway County's Poor-condition bridges carry 33,940 vehicle crossings a day
That is 31.5% of the county's reported daily bridge traffic on 11.6% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 3,394 crossings a day against 318 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 86 of 100 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
22% of Ketchikan Gateway County's bridges have passed the 50-year mark
22 of the 100 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 43% 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 41.4% of the county's Poor-condition bridge traffic
SOUTH TONGASS HWY over WATER ST VIADUCT, built 1955, carries 14,046 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 12-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 33,940 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Ketchikan Gateway County's bridges were built
100 bridges with a recorded construction year, grouped by decade
- 1930s 1
1930–1939
1 bridges
- 1940s 1
1940–1949
1 bridges
- 1950s 6
1950–1959
6 bridges
- 1960s 10
1960–1969
10 bridges
- 1970s 7
1970–1979
7 bridges
- 1980s
1980–1989
15 bridges
- 1990s
1990–1999
14 bridges
- 2000s
2000–2009
16 bridges
- 2010s
2010–2019
28 bridges
- 2020s 2
2020–2029
2 bridges
What this shows Construction peaked in the 2010s, when 28 of the county's bridges still in the inventory were built, which is 28% of those with a recorded year. That cohort is now 5 to 14 years old in the 2024 inventory. Its average build year (1993) matches the Alaska average (1989).
How Ketchikan Gateway County compares with Alaska's closest counties by inventory size
The 5 Alaska counties nearest Ketchikan Gateway County in number of bridges, with their condition splits. Its 12% Poor share is the 4th-lowest of these 6. Its average build year of 1993 against a peer-group mean of 1988 is 5 years newer.
Showing the 5 closest of 26 Alaska counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Hoonah-Angoon County | 125 | 49.6% | 35.2% | 15.2% | 1994 |
| 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 (this page) | 100 | 43% | 45% | 12% | 1993 |
| Yukon-Koyukuk County | 94 | 41.5% | 50% | 8.5% | 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 Ketchikan Gateway 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 Ketchikan Gateway County, both outside Alaska so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside AK (100 bridges here).
- Gunnison County, CO · 100 bridges
- Monroe County, FL · 100 bridges
- Fayette County, IN · 100 bridges
- LaGrange County, IN · 100 bridges
Similar average build year
Nearest mean year-built outside AK (1993 here).
- Salt Lake County, UT · avg 1993 · 659 bridges
- Marshall County, MS · avg 1993 · 255 bridges
- Rowan County, NC · avg 1993 · 245 bridges
- Cabarrus County, NC · avg 1993 · 236 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Poor-condition bridges (12)
PARK/HARRIS ST
PoorOver: KETCHIKAN CREEK
MILE POINT 0.1, Ketchikan Gateway, AK
Built 1957 Load: 5.0 t ADT: 2,512
NO DATA ENTERED
PoorOver: MOD
MARGARET, Ketchikan Gateway, AK
Built 1989 Load: 8.1 t
HARDING STREET
PoorOver: HARDING STREET
MILE POINT 0.1, Ketchikan Gateway, AK
Built 1968 Load: 14.4 t ADT: 30
PETERSON STREET
PoorOver: PETERSON STREET
MILE POINT 0.1, Ketchikan Gateway, AK
Built 1955 Load: 17.5 t ADT: 30
SAYLES/GORGE ST
PoorOver: SAYLES/GORGE VIADUCT
MILE POINT 0.1, Ketchikan Gateway, AK
Built 1960 Load: 19.2 t ADT: 40
8400000
PoorOver: TRAIL # 828400SHOAL
SHOAL COVE, Ketchikan Gateway, AK
Built 1992 Load: 19.8 t ADT: 5
SHELTER COVE ROAD
PoorOver: HARRIET HUNT CREEK
MILE POINT 2.7, Ketchikan Gateway, AK
Built 1981 Load: 25.0 t ADT: 125
SOUTH TONGASS HWY
PoorOver: HOADLEY CREEK
MILE POINT 0.2, Ketchikan Gateway, AK
Built 1957 Load: 26.5 t ADT: 11,900
8330000
PoorOver: MOD
SHELTER, Ketchikan Gateway, AK
Built 1992 Load: 26.9 t
SOUTH TONGASS HWY
PoorOver: WATER ST VIADUCT
MILE POINT 1.7, Ketchikan Gateway, AK
Built 1955 Load: 27.1 t ADT: 14,046
NORTH TONGASS HWY
PoorOver: WARD CREEK
MILE POINT 4.6, Ketchikan Gateway, AK
Built 1975 Load: 29.8 t ADT: 5,250
NO DATA ENTERED
PoorOver: PERM
UPPER CARROLL, Ketchikan Gateway, AK
Built 1997 Load: 32.7 t ADT: 2
Read our methodology - how this data is sourced, computed, and verified.
Related
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.