Petersburg County, AK

115 public highway bridges

Petersburg County Bridge Snapshot

Petersburg County, Alaska contains 115 public highway bridges in the FHWA National Bridge Inventory. Roughly 46.1% are rated “Good,” 45.2% “Fair,” 8.7% “Poor,” and 8.7% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in AK are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

115

Total Bridges

46.1%

Good

8.7%

Poor

8.7%

Structurally Deficient

Condition Distribution

Good

46.1% (53)

Fair

45.2% (52)

Poor

8.7% (10)

SD

8.7% (10)

All Bridges (115)

Sort:

LOGGING ROAD

Over: STREAM

MITKOF ISLAND, Petersburg, AK

Built 1974 Load: 15.2 t ADT: 50

LOGGING ROAD

Over: STREAM

MITKOF ISLAND, Petersburg, AK

Built 1987 Load: 16.2 t ADT: 30

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1984 Load: 16.2 t ADT: 5

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1985 Load: 16.2 t

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1984 Load: 16.2 t ADT: 5

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1985 Load: 16.2 t ADT: 5

LOGGING ROAD

Over: CREEK

MITKOF ISLAND, Petersburg, AK

Built 1984 Load: 16.2 t

NO DATA ENTERED

Over: NO DATA ENTERED

MITKOF ISLAND, Petersburg, AK

Built 2005 Load: 16.8 t ADT: 10

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND, PORTAGE, Petersburg, AK

Built 1981 Load: 17.2 t

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND, PORTAGE, Petersburg, AK

Built 1980 Load: 17.8 t

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1978 Load: 18.8 t

LOGGING ROAD

Over: STREAM

TONKA, Petersburg, AK

Built 1979 Load: 19.8 t ADT: 10

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND AT KAKE, Petersburg, AK

Built 1979 Load: 19.8 t ADT: 10

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND, PORTAGE, Petersburg, AK

Built 1990 Load: 19.8 t

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1987 Load: 19.8 t ADT: 5

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1982 Load: 19.8 t

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND, PORTAGE, Petersburg, AK

Built 1990 Load: 19.8 t

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1982 Load: 19.8 t

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1991 Load: 19.8 t

ROAD

Over: STREAM

KUPREANOF ISLAND, PORTAGE, Petersburg, AK

Built 1981 Load: 19.8 t

ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1979 Load: 19.8 t

NO DATA ENTERED

Over: NO DATA ENTERED

MITKOF ISLAND, Petersburg, AK

Built 1979 Load: 19.8 t ADT: 10

NO DATA ENTERED

Over: NO DATA ENTERED

TONKA, Petersburg, AK

Built 2006 Load: 22.0 t ADT: 5

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND AT KAKE, Petersburg, AK

Built 1978 Load: 23.7 t ADT: 10

LOGGING ROAD

Over: NO DATA ENTERED

KUIU ISLAND, Petersburg, AK

Built 1979 Load: 23.7 t

MITKOF HIGHWAY

Over: FALLS CREEK

MILE POINT 9.7, Petersburg, AK

Built 1967 Load: 29.1 t ADT: 180

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1993 Load: 31.8 t

LOGGING ROAD

Over: NO DATA ENTERED

KUIU ISLAND, Petersburg, AK

Built 1993 Load: 31.8 t

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND AT KAKE, Petersburg, AK

Built 1997 Load: 32.7 t ADT: 10

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND, PORTAGE, Petersburg, AK

Built 1996 Load: 32.7 t

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1977 Load: 32.7 t ADT: 5

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1977 Load: 32.7 t ADT: 5

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND AT KAKE, Petersburg, AK

Built 1998 Load: 32.7 t ADT: 10

NO DATA ENTERED

Over: NO DATA ENTERED

THOMAS BAY, Petersburg, AK

Built 2003 Load: 32.7 t ADT: 10

NO DATA ENTERED

Over: NO DATA ENTERED

TONKA, Petersburg, AK

Built 2006 Load: 34.0 t ADT: 5

LOGGING ROAD

Over: STREAM

TONKA, Petersburg, AK

Built 1980 Load: 36.3 t ADT: 5

43500

Over: LOG

TONKA, Petersburg, AK

Built 2002 Load: 42.1 t ADT: 5

LOGGING ROAD

Over: STREAM

KUIU ISLAND, Petersburg, AK

Built 1990 Load: 42.4 t

LOGGING ROAD

Over: STREAM

KUPREANOF ISLAND, PORTAGE, Petersburg, AK

Built 1980 Load: 43.1 t

LOGGING ROAD

Over: STREAM

TONKA, Petersburg, AK

Built 2014 Load: 45.0 t ADT: 10

LOGGING ROAD

Over: STREAM

MITKOF ISLAND, Petersburg, AK

Built 1988 Load: 49.9 t ADT: 10

NO DATA ENTERED

Over: NO DATA ENTERED

TONKA, Petersburg, AK

Built 2006 Load: 50.5 t ADT: 5

NO DATA ENTERED

Over: NO DATA ENTERED

TONKA, Petersburg, AK

Built 2004 Load: 50.9 t ADT: 5

43500

Over: LOG

TONKA, Petersburg, AK

Built 2002 Load: 52.2 t ADT: 5

NO DATA ENTERED

Over: NO DATA ENTERED

TONKA, Petersburg, AK

Built 2006 Load: 55.4 t ADT: 5

LOGGING ROAD

Over: STREAM

MITKOF ISLAND, Petersburg, AK

Built 1980 Load: 56.1 t ADT: 50

ROAD

Over: STREAM

TONKA, Petersburg, AK

Built 2004 Load: 59.9 t ADT: 5

LOGGING ROAD

Over: STREAM

TONKA, Petersburg, AK

Built 1976 Load: 60.6 t ADT: 5

NO DATA ENTERED

Over: NO DATA ENTERED

KUPREANOF ISLAND, PORTAGE, Petersburg, AK

Built 2006 Load: 66.1 t

ROAD

Over: STREAM

TONKA, Petersburg, AK

Built 2004 Load: 71.6 t ADT: 5

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

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Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 6, 2026