Siskiyou County, CA

423 public highway bridges

Siskiyou County Bridge Snapshot

Siskiyou County, California contains 423 public highway bridges in the FHWA National Bridge Inventory. Roughly 36.2% are rated “Good,” 49.6% “Fair,” 5.4% “Poor,” and 5.4% 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 CA 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.

423

Total Bridges

36.2%

Good

5.4%

Poor

5.4%

Structurally Deficient

Condition Distribution

Good

36.2% (153)

Fair

49.6% (210)

Poor

5.4% (23)

SD

5.4% (23)

All Bridges (423)

Sort:

U.S. HIGHWAY 97

Over: SHEEP ROCK CATTLEPASS

02-SIS-097-R14.65, Siskiyou, CA

Built 1976 Load: 32.4 t ADT: 3,250

STATE ROUTE 3

Over: KIDDER CREEK

02-SIS-003-27.09, Siskiyou, CA

Built 1956 Load: 32.4 t ADT: 2,825

STATE ROUTE 3

Over: KIDDER CREEK

02-SIS-003-31.23, Siskiyou, CA

Built 1956 Load: 32.4 t ADT: 2,825

STATE ROUTE 161

Over: OREGON DRAIN

02-SIS-161-3.48, Siskiyou, CA

Built 1946 Load: 32.4 t ADT: 655

U.S. HIGHWAY 97

Over: CORP RR

02-SIS-097-0.15-WEED, Siskiyou, CA

Built 1982 Load: 32.4 t ADT: 18,000

U.S. HIGHWAY 97

Over: WHITNEY CREEK

02-SIS-097-9.61, Siskiyou, CA

Built 1982 Load: 32.4 t ADT: 5,000

STATE ROUTE 96

Over: KOHL CREEK

02-SIS-096-80.05, Siskiyou, CA

Built 1953 Load: 32.4 t ADT: 650

INTERSTATE 5

Over: YREKA CREEK

02-SIS-005-R45.61-YRE, Siskiyou, CA

Built 1970 Load: 32.4 t ADT: 16,600

STATE ROUTE 3

Over: ETNA CREEK

02-SIS-003-20.44, Siskiyou, CA

Built 1959 Load: 32.4 t ADT: 880

I-5 OFFRMP/KLAMATH

Over: WILLIAMS CREEK

02-SIS-005-R58.10L, Siskiyou, CA

Built 1969 Load: 32.4 t ADT: 60

HIGHWAY 96

Over: O'NEIL CREEK

02-SIS-096-65.38, Siskiyou, CA

Built 2008 Load: 32.4 t ADT: 600

STATE ROUTE 161

Over: LOST RIVER

02-SIS-161-19.18, Siskiyou, CA

Built 2008 Load: 32.4 t ADT: 655

GAZELLE-CALLAHAN R

Over: SOUTH FORK WILLOW CREEK

4.6 MI W OLD HY 99, Siskiyou, CA

Built 1973 Load: 32.4 t ADT: 306

HENLEY-HORNBROK RD

Over: COTTONWOOD CREEK

0.10 MI E HORNBROOK RD, Siskiyou, CA

Built 1989 Load: 32.4 t ADT: 377

ISLAND ROAD

Over: SCOTT RIVER OVERFLOW

0.75 MI W OF E ROAD, Siskiyou, CA

Built 1989 Load: 32.4 t ADT: 35

WALKER ROAD CONN

Over: KLAMATH RIVER

0.025 KM S SR 96, Siskiyou, CA

Built 1997 Load: 32.4 t ADT: 125

ISLAND RD

Over: SCOTT RIVER OVERFLOW

0.3 MI E SERPA LANE, Siskiyou, CA

Built 1986 Load: 32.4 t ADT: 170

AGER BESWICK ROAD

Over: BOGUS CREEK

7.6 MI EAST OF AGER ROAD, Siskiyou, CA

Built 2002 Load: 32.4 t ADT: 100

HORSE CREEK ROAD

Over: MIDDLE CREEK

2.5 MI N OF SR 96, Siskiyou, CA

Built 1971 Load: 32.4 t ADT: 21

SCOTT RIVER RD

Over: MCGUFFY CREEK

2.7 MI S MILL CRK RD, Siskiyou, CA

Built 1979 Load: 32.4 t ADT: 39

MOFFETT CREEK RD

Over: MOFFETT CREEK

2.6 MI EAST SR 3, Siskiyou, CA

Built 1989 Load: 32.4 t ADT: 145

OLD HWY 99

Over: WILLOW CREEK

1.0 MI S GAZELLE-CALLAHAN, Siskiyou, CA

Built 1994 Load: 32.4 t ADT: 1,005

DUZEL CREEK RD

Over: DUZEL CREEK

0.2 MI SW SCARFACE RD, Siskiyou, CA

Built 1974 Load: 32.4 t ADT: 15

KLAMATH RIVER ROAD

Over: VESA CREEK

7 MI NW HUMBUG CR RD, Siskiyou, CA

Built 1974 Load: 32.4 t ADT: 23

COPCO ROAD

Over: JENNY CREEK

COPCO ROAD, Siskiyou, CA

Built 2008 Load: 32.4 t ADT: 50

STATE ROUTE 96

Over: KLAMATH RIVER

02-SIS-096-61.14, Siskiyou, CA

Built 1954 Load: 32.7 t ADT: 600

STATE ROUTE 3

Over: FRENCH CREEK

02-SIS-003-16.87, Siskiyou, CA

Built 1959 Load: 32.7 t ADT: 880

SECOND AVENUE

Over: INDIAN CREEK

AT INDIAN CREEK RD, Siskiyou, CA

Built 1966 Load: 32.7 t ADT: 1,936

PATROL RD UNIT 3A

Over: CANAL TURNOUT

CENTER PATROL RD/UNIT 3A, Siskiyou, CA

Built 1953 Load: 32.7 t

AUTO TOUR ROAD

Over: CANAL TURNOUT

SW CORNER UNIT 4A, Siskiyou, CA

Built 1963 Load: 32.7 t ADT: 50

SAWYERS BAR RD

Over: LITTLE N FK SALMON RIVER

1 MI W KELLEY GULCH RD, Siskiyou, CA

Built 1968 Load: 33.0 t ADT: 120

STATE ROUTE 263

Over: SHASTA RIVER

02-SIS-263-52.62, Siskiyou, CA

Built 1928 Load: 33.4 t ADT: 1,200

INTERSTATE 5

Over: PARKS CREEK

02-SIS-005-R27.18, Siskiyou, CA

Built 1969 Load: 33.4 t ADT: 7,400

W. A. BARR RD

Over: SACRAMENTO RIVER

1.5 MI S OF W REAM AVE, Siskiyou, CA

Built 1968 Load: 34.0 t ADT: 864

BUKER ROAD

Over: KELSEY CREEK

SCOTT BAR, Siskiyou, CA

Built 1984 Load: 34.3 t ADT: 15

SALMON RIVER ROAD

Over: NORDHEIMER CREEK

4 MI N/O SAWYERS BAR RD, Siskiyou, CA

Built 1967 Load: 34.7 t ADT: 93

SCOTT RIVER ROAD

Over: SCOTT RIVER

1.2 MI SOUTH OF SR 96, Siskiyou, CA

Built 1967 Load: 35.0 t ADT: 186

BOULDER CREEK RD

Over: BOULDER CREEK

0.4 MI E CANYON CRK RD, Siskiyou, CA

Built 1993 Load: 35.3 t ADT: 8

INTERSTATE 5

Over: DEETZ ROAD

02-SIS-005-R15.32, Siskiyou, CA

Built 1973 Load: 36.0 t ADT: 12,300

INTERSTATE 5

Over: PANORAMA ROAD

02-SIS-005-1.21, Siskiyou, CA

Built 1960 Load: 36.3 t ADT: 18,000

QUARTZ VALLEY ROAD

Over: MILL CREEK

0.1 MI W E. QUARTZ VALLEY, Siskiyou, CA

Built 1980 Load: 36.6 t ADT: 395

STATE ROUTE 96

Over: KLAMATH RIVER

02-SIS-096-77.15, Siskiyou, CA

Built 1953 Load: 36.9 t ADT: 650

INTERSTATE 5

Over: PARKS CREEK

02-SIS-005-R27.18, Siskiyou, CA

Built 1969 Load: 36.9 t ADT: 7,400

WYEHKA WAY

Over: WAGON CREEK

0.1 MI W OLD STAGE RD, Siskiyou, CA

Built 1968 Load: 36.9 t ADT: 143

INTERSTATE 5

Over: DUNSMUIR AVE

02-SIS-005-0.69, Siskiyou, CA

Built 1960 Load: 37.3 t ADT: 18,000

INTERSTATE 5

Over: DUNSMUIR AVE

02-SIS-005-2.51-DMR, Siskiyou, CA

Built 1960 Load: 37.3 t ADT: 18,000

STATE ROUTE 3

Over: EAST FORK SCOTT RIVER

02-SIS-003-8.66, Siskiyou, CA

Built 1968 Load: 37.3 t ADT: 190

SAWYERS BAR RD

Over: NORTH RUSSIAN CREEK

4.7 MI N WHITES GULCH RD, Siskiyou, CA

Built 1968 Load: 37.3 t ADT: 105

ELK CREEK ROAD

Over: KLAMATH RIVER

0.3 MI S OF SH 96, Siskiyou, CA

Built 1953 Load: 37.3 t ADT: 1,392

INTERSTATE 5

Over: CRAM GULCH

02-SIS-005-R39.02, Siskiyou, CA

Built 1969 Load: 37.6 t ADT: 7,850

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