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.

1900s

1
1910s

4
1920s

1
1930s

12
1940s

9
1950s

41
1960s

46
1970s

15
1980s

16
1990s

3
2000s

6
2010s

8
2020s

3

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.

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	Good	Fair	Poor	Avg. built
El Dorado County	192	46.9%	46.9%	6.3%	1975
Santa Cruz County	192	40.1%	42.2%	17.7%	1963
Kings County	168	40.5%	53.6%	6%	1968
Plumas County (this page)	165	26.7%	69.1%	4.2%	1965
Napa County	158	45.6%	50%	4.4%	1961
San Francisco County	143	34.3%	51%	14.7%	1969

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).

Cleburne County, AL · 165 bridges
Randolph County, AL · 165 bridges
Leon County, FL · 165 bridges
Hamilton County, IL · 165 bridges

Similar average build year

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

Windsor County, VT · avg 1965 · 483 bridges
Bedford County, PA · avg 1965 · 417 bridges
Crawford County, PA · avg 1965 · 399 bridges
Harper County, KS · avg 1965 · 372 bridges

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

Fair-condition bridges (114)

Sort:

Plumas County Bridge Snapshot

Condition distribution

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

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

One structure carries 97.2% of the county's Poor-condition bridge traffic

How Plumas County compares with California'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 (114)

CHANDLER ROAD

HARRIET LANE

HARRLET LN

DYSON LANE

DYSON LANE

DYSON LANE

DYSON LANE

HARRIET LANE

LAKE DAVIS ROAD

DRYSON LANE

DYSON LANE

DYSON LANE

DYSON LANE

ROUND HOUSE RD

STATE ROUTE 70

BECKWTH GRNVLE RD

BECKWORTH GENESEE

CLIO-STATE 40A RD

WARNER VALLEY RD

SPANISH RANCH RD

GULLING STREET

DYSON LANE

BECKWOURTH GRNVLE

STATE ROUTE 284

STATE ROUTE 284

STATE ROUTE 70

MOHAWK HWY

QUINCY-LA PORTE RD

QUINCY-LA PORTE RD

MAIN STREET

VIRGILIA ROAD

SENECA ROAD

DOTTA-GUIDICCI RD

BKWTH GRNVILLE RD

STATE ROUTE 70

PAXTON RD

HUMBUG RD

QUINCY JUNCTION RD

SETZER CAMP RD

OLD RED BLUFF RD

BUTTERFLY VLY RD

FEATHER RIVER DR

STATE ROUTE 89

BUCKS LAKE ROAD

DIAMOND MOUNTAN RD

GRNVLE RND VLY RD

BECKWRTH-GENESSEE

DIAMOND MTN RD

STAMPFLI LN

PORT WINE ROAD

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