County profile · official public datasets

Plumas County, CA

165 public highway bridges tracked in the FHWA National Bridge Inventory: 26.7% rated Good, 69.1% Fair, 4.2% Poor.

165
Public bridges
26.7%
Good condition
4.2%
Poor condition

The verdict

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

Plumas County pairs a top-quartile lowest Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 22%
lowest Poor share in state
4.2%
Poor-condition share
165
public highway bridges
1965
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.

Plumas County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Plumas County ranks #13 of 58 California counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.2%). Plumas County, California contains 165 public highway bridges. Roughly 26.7% are rated “Good,” 69.1% “Fair,” and 4.2% “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

165

Public highway bridges in Plumas County

Good condition

26.7%

44 of 165 rated 7-9

Fair condition

69.1%

114 of 165 rated 5-6

Poor condition

4.2%

7 of 165 rated 4 or below

In-state Poor-share rank

#13 of 58

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

Condition distribution

Share of 165 NBI-tracked bridges by lowest applicable component rating.

Good
26.7% (44)
Fair
69.1% (114)
Poor
4.2% (7)

Plumas County's Poor-condition bridges carry 10,336 vehicle crossings a day

That is 8.3% of the county's reported daily bridge traffic on 4.2% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 1,477 crossings a day against 1,176 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 165 of 165 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

73.9% of Plumas County's bridges have passed the 50-year mark

122 of the 165 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 26.7% 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 97.2% of the county's Poor-condition bridge traffic

GULLING STREET over MIDDLE FORK FEATHER RIV, built 1954, carries 10,046 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 7-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 10,336 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Plumas County's bridges were built

165 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1960s, when 46 of the county's bridges still in the inventory were built, which is 27.9% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1965, 5 years older than the California average of 1970.

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

How Plumas County compares with California's closest counties by inventory size

The 5 California counties nearest Plumas County in number of bridges, with their condition splits. Its 4.2% Poor share is the 1st-lowest of these 6. Its average build year of 1965 against a peer-group mean of 1967 is in line with the group.

Showing the 5 closest of 57 California counties eligible for comparison.

Bridge inventory size and condition shares for Plumas County and the 5 California counties closest to it in inventory size
County Bridges Poor
El Dorado County 192 6.3%
Santa Cruz County 192 17.7%
Kings County 168 6%
Plumas County (this page) 165 4.2%
Napa County 158 4.4%
San Francisco County 143 14.7%

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 Plumas 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 Plumas County, both outside California so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside CA (165 bridges here).

Similar average build year

Nearest mean year-built outside CA (1965 here).

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 165 Good 44 Fair 114 Poor 7

All bridges (165)

1ST AVENUE

Fair

Over: NORTH FORK FEATHER RIVER

0.1 MI S OF S.H. 36, Plumas, CA

Built 1947 Load: 40.8 t ADT: 960

STAMPFLI LANE

Fair

Over: INDIAN CREEK

2.9 MI E SR 89, Plumas, CA

Built 1965 Load: 41.1 t ADT: 400

RICH GULCH RD

Fair

Over: RUSH CREEK

0.4 MI N OF SR 70, Plumas, CA

Built 1955 Load: 41.1 t ADT: 30

HUMBUG ROAD

Fair

Over: BUTT CREEK

1.2 MI W HUMBG-HUMBLT RD, Plumas, CA

Built 1960 Load: 42.4 t ADT: 35

DIXIE CNYN RD

Fair

Over: ROUND VALLEY LAKE OUTLET

2.9 MI SW OF SH 89, Plumas, CA

Built 1930 Load: 42.4 t ADT: 55

ROAD 21N02

Fair

Over: SULPHUR CREEK

SULPHUR CREEK, Plumas, CA

Built 1964 Load: 42.8 t ADT: 50

STATE ROUTE 70

Fair

Over: INDIAN CREEK

02-PLU-070-33.07, Plumas, CA

Built 1954 Load: 43.1 t ADT: 3,375

BUCKS LAKE ROAD

Fair

Over: ROCK CREEK

4.3 MI W/O SR 70, Plumas, CA

Built 1969 Load: 43.4 t ADT: 1,700

BECKWRTH-GEHN RD

Fair

Over: INDIAN CREEK

400 FT S OF INDIAN CR RD, Plumas, CA

Built 1956 Load: 46.3 t ADT: 10

ST LOUIS RD

Fair

Over: SLATE CREEK

AT PLUMAS CO LINE, Plumas, CA

Built 1990 Load: 47.3 t ADT: 50

BECKWORTH CALPINE

Fair

Over: MIDDLE FORK FEATHER RIV

0.2 MI SOUTH OF SH 70, Plumas, CA

Built 1961 Load: 48.9 t ADT: 1,090

DYSON LANE

Fair

Over: MID FK FEATHER RIV OVRFL

0.8 MI E BCKWRTH-CALPN RD, Plumas, CA

Built 1959 Load: 48.9 t ADT: 22

HUMBOLDT ROAD

Fair

Over: SOLDIERS MEADOW CREEK

5.0 MI W OF SH 89, Plumas, CA

Built 1970 Load: 49.9 t ADT: 40

DIAMOND MTN RD

Fair

Over: LIGHTS CREEK

4.9 MI NE GRNVLE-BECK RD, Plumas, CA

Built 1956 Load: 58.6 t ADT: 70

NO DATA ENTERED

Good

Over: WEST BRANCH LIGHTS CREEK

NO DATA ENTERED, Plumas, CA

Built 2022 ADT: 2

ROAD 23N08

Good

Over: POPLAR CREEK

POPLAR CREEK, Plumas, CA

Built 1966 ADT: 50

ROAD 24N85Y

Good

Over: BIG GRIZZLY CREEK

BIG GRIZZLY CREEK, Plumas, CA

Built 1974 ADT: 50

ROAD 22N94

Good

Over: SOUTH BR MIDDLE FORK

NO DATA ENTERED, Plumas, CA

Built 1957 ADT: 60

ROAD 22N94

Good

Over: LGV DAM SPILLWAY APPROCH

500 FT NORTH OF LGV DAM, Plumas, CA

Built 1966 ADT: 50

ROAD 23N10

Good

Over: EAST BRANCH HOPKINS CREK

NO DATA ENTERED, Plumas, CA

Built 1984 ADT: 50

ROAD 22N57

Good

Over: LOWER KENZIE RAVINE

NO DATA ENTERED, Plumas, CA

Built 1960 ADT: 40

ROAD 27N26

Good

Over: MOSQUITO CREEK

CARIBOU ROAD, Plumas, CA

Built 1984 ADT: 50

ROAD 27N17

Good

Over: RUSH CREEK

RUSH CREEK, Plumas, CA

Built 1977 ADT: 25

GREENVILLE PARK RD

Good

Over: WOLF CREEK

0.1 MI S HOT SPRINGS RD, Plumas, CA

Built 1987 Load: 13.9 t ADT: 50

ARLINGTON RD

Good

Over: INDIAN CREEK

0.1 MI W/O BCKW-GRNV RD, Plumas, CA

Built 1964 Load: 19.4 t ADT: 280

21N10 IN L.B. CG

Good

Over: GRAY EAGLE CK

WITHIN CAMPGROUND, Plumas, CA

Built 1995 Load: 20.7 t ADT: 50

ROAD 26N04

Good

Over: LAST CHANCE CREEK

LAST CHANCE CREEK, Plumas, CA

Built 1973 Load: 21.1 t ADT: 50

STATE ROUTE 70

Good

Over: NORTH FORK FEATHER RIVER

02-PLU-070-5.58, Plumas, CA

Built 1936 Load: 22.4 t ADT: 1,345

ARLINGTON RD

Good

Over: INDIAN CREEK

0.1 MI E/O SR 89, Plumas, CA

Built 1964 Load: 22.7 t ADT: 780

STATE ROUTE 89

Good

Over: GRAEAGLE CREEK

02-PLU-089-7.29, Plumas, CA

Built 1954 Load: 24.3 t ADT: 2,025

STATE ROUTE 70

Good

Over: CLEAR STREAM

02-PLU-070-42.86, Plumas, CA

Built 1937 Load: 24.3 t ADT: 6,700

ROAD 26N70

Good

Over: DIXIE CREEK

DIXIE CREEK, Plumas, CA

Built 2002 Load: 24.6 t ADT: 150

STATE ROUTE 70

Good

Over: UP RR & BNSF RY

02-PLU-070-35.56, Plumas, CA

Built 1932 Load: 25.9 t ADT: 3,375

STATE ROUTE 147

Good

Over: HAMILTON BRANCH CREEK

02-PLU-147-8.98, Plumas, CA

Built 2018 Load: 26.9 t ADT: 1,525

SLOAT ROAD

Good

Over: LONG VALLEY CREEK

1.2 MI S/W SH 70, Plumas, CA

Built 1989 Load: 26.9 t ADT: 180

STATE ROUTE 36

Good

Over: BAILEY CREEK

02-PLU-036-R13.73, Plumas, CA

Built 1966 Load: 28.5 t ADT: 5,000

STATE ROUTE 89

Good

Over: FRAZIER CREEK

02-PLU-089-6.29, Plumas, CA

Built 1954 Load: 29.5 t ADT: 1,015

STATE ROUTE 70

Good

Over: CHAMBERS CREEK

02-PLU-070-9.04, Plumas, CA

Built 1959 Load: 32.4 t ADT: 1,345

STATE ROUTE 89

Good

Over: SULPHUR CREEK

02-PLU-089-3.40, Plumas, CA

Built 2002 Load: 32.4 t ADT: 1,015

STATE ROUTE 89

Good

Over: BNSF RY

02-PLU-089-19.90, Plumas, CA

Built 1988 Load: 32.4 t ADT: 3,050

STATE ROUTE 89

Good

Over: WOLF CREEK

02-PLU-089-20.01, Plumas, CA

Built 1988 Load: 32.4 t ADT: 3,050

STATE ROUTE 70

Good

Over: GREENHORN CR UP RR BNSF

02-PLU-070-51.21, Plumas, CA

Built 1956 Load: 32.4 t ADT: 3,425

STATE ROUTE 284

Good

Over: LITTLE LAST CHANCE CREEK

02-PLU-284-7.01, Plumas, CA

Built 2000 Load: 32.4 t ADT: 640

STATE ROUTE 70

Good

Over: YELLOW CREEK

02-PLU-070-14.90, Plumas, CA

Built 2020 Load: 32.4 t ADT: 1,345

STATE ROUTE 89

Good

Over: LAKE ALMANOR SPILLWAY

02-PLU-089-29.97, Plumas, CA

Built 2018 Load: 32.4 t ADT: 1,150

JOHNSVILLE ROAD

Good

Over: JAMISON CREEK

5.1 MI W SH 89, Plumas, CA

Built 2003 Load: 32.4 t ADT: 560

CR 413 SPN RCH RD

Good

Over: SPANISH CREEK

0.1 MI N BUCKS LAKE RD, Plumas, CA

Built 2021 Load: 32.4 t ADT: 80

COUNTY ROAD 322A

Good

Over: BAILEY CREEK

W OF CR 322 N OF CA 36, Plumas, CA

Built 2016 Load: 32.4 t ADT: 25

CHSTR-WARNER VLYRD

Good

Over: WARNER CREEK

C.R. 312, Plumas, CA

Built 2011 Load: 32.4 t ADT: 280

NO DATA ENTERED

Good

Over: JACKASS CREEK

NO DATA ENTERED, Plumas, CA

Built 2017 Load: 33.0 t ADT: 50

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

Related

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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.