County profile · official public datasets

Lassen County, CA

108 public highway bridges tracked in the FHWA National Bridge Inventory: 25.9% rated Good, 65.7% Fair, 8.3% Poor.

108
Public bridges: 25.9%
Good condition: 8.3%
Poor condition

The verdict

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

Lassen County posts a higher-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

40th
of 58 on Poor share: 8.3%
Poor-condition share: 108
public highway bridges: 1968
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.

Lassen County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Lassen County ranks #40 of 58 California counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.3%). Lassen County, California contains 108 public highway bridges. Roughly 25.9% are rated “Good,” 65.7% “Fair,” and 8.3% “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

108

Public highway bridges in Lassen County

Good condition

25.9%

28 of 108 rated 7-9

Fair condition

65.7%

71 of 108 rated 5-6

Poor condition

8.3%

9 of 108 rated 4 or below

In-state Poor-share rank

#40 of 58

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

Condition distribution

Share of 108 NBI-tracked bridges by lowest applicable component rating.

Good

25.9% (28)

Fair

65.7% (71)

Poor

8.3% (9)

Lassen County's Poor-condition bridges carry 2,482 vehicle crossings a day

That is 1.4% of the county's reported daily bridge traffic on 8.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 276 crossings a day against 2,480 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 108 of 108 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

53.7% of Lassen County's bridges have passed the 50-year mark

58 of the 108 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 25.9% 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 60.4% of the county's Poor-condition bridge traffic

CR A21 / MOONEY RD over ROBBERS CREEK, built 1975, carries 1,500 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 9-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 2,482 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

15
1930s

5
1940s

2
1950s

9
1960s

20
1970s

34
1980s

7
1990s

5
2000s

3
2010s

5
2020s

3

What this shows Construction peaked in the 1970s, when 34 of the county's bridges still in the inventory were built, which is 31.5% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1968) matches the California average (1970).

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

The 5 California counties nearest Lassen County in number of bridges, with their condition splits. Its 8.3% Poor share is the 3rd-lowest of these 6. Its average build year of 1968 against a peer-group mean of 1965 is in line with the group.

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

Bridge inventory size and condition shares for Lassen County and the 5 California counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Tuolumne County	125	36%	56.8%	7.2%	1964
Sutter County	121	33.9%	52.9%	13.2%	1968
Mariposa County	109	21.1%	67.9%	11%	1956
Lassen County (this page)	108	25.9%	65.7%	8.3%	1968
Calaveras County	105	33.3%	60%	6.7%	1962
Del Norte County	96	51%	37.5%	11.5%	1975

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

Similar inventory size

Nearest county inventories outside CA (108 bridges here).

Pulaski County, IL · 108 bridges
West Feliciana County, LA · 108 bridges
Brown County, MN · 108 bridges
Shelby County, MO · 108 bridges

Similar average build year

Nearest mean year-built outside CA (1968 here).

Montgomery County, PA · avg 1968 · 828 bridges
Providence County, RI · avg 1968 · 476 bridges
Delaware County, PA · avg 1968 · 387 bridges
Genesee County, MI · avg 1968 · 371 bridges

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

All 108 Good 28 Fair 71 Poor 9

All bridges (108)

Sort:

Lassen County Bridge Snapshot

Condition distribution

Lassen County's Poor-condition bridges carry 2,482 vehicle crossings a day

53.7% of Lassen County's bridges have passed the 50-year mark

One structure carries 60.4% of the county's Poor-condition bridge traffic

How Lassen 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

All bridges (108)

ROAD 30N06

CR 417(PUNKIN CTR)

RD 304

RD 318

CR306 (CAPEZOLLI)

RD 304 (ALEXANDER)

RD 305 (MAPES RD)

CR527 (ASH VALLEY)

SCOTT ROAD

EAGLE LAKE RD

TRAVIS LANE

U.S. HIGHWAY 395

SCOTT RD

U.S. HIGHWAY 395

RD 305

CENTER RD

RD 315

RD 303 (GALEPPI)

BIEBER LOOKOUT RD

RD 304

COUNTY ROAD 311

C.R. 353

C.R. 353

C.R. 353

JOHNSTONVILLE RD

JOHNSTONVILLE RD

C.R. 301

SURPRISE VALLEY RD

ROAD 30N03

STATE ROUTE 299

STATE ROUTE 299

STATE ROUTE 299

STATE ROUTE 299

RD 304

CR213 (LEAVITT LN)

C.R. 203

C.R. 203

RD 306 (CAPEZOLLI)

STATE ROUTE 70

CR213 (LEAVITT LN)

STATE ROUTE 299

U.S. HIGHWAY 395

STATE ROUTE 299

GARNIER RD

U.S. HIGHWAY 395

STATE ROUTE 36

U.S. HIGHWAY 395

STATE ROUTE 70

U.S. HIGHWAY 395

FISH AND GAME ROAD

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