County profile · official public datasets

Butte County, CA

437 public highway bridges tracked in the FHWA National Bridge Inventory: 31.8% rated Good, 62% Fair, 6.2% Poor.

437
Public bridges: 31.8%
Good condition: 6.2%
Poor condition

The verdict

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

Butte County pairs a better-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 40%
lowest Poor share in state: 6.2%
Poor-condition share: 437
public highway bridges: 1958
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.

Butte County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Butte County ranks #23 of 58 California counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.2%). Butte County, California contains 437 public highway bridges. Roughly 31.8% are rated “Good,” 62% “Fair,” and 6.2% “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

437

Public highway bridges in Butte County

Good condition

31.8%

139 of 437 rated 7-9

Fair condition

62%

271 of 437 rated 5-6

Poor condition

6.2%

27 of 437 rated 4 or below

In-state Poor-share rank

#23 of 58

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

Condition distribution

Share of 437 NBI-tracked bridges by lowest applicable component rating.

Good

31.8% (139)

Fair

62% (271)

Poor

6.2% (27)

Butte County's Poor-condition bridges carry 90,044 vehicle crossings a day

That is 4% of the county's reported daily bridge traffic on 6.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 3,335 crossings a day against 7,855 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 437 of 437 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

78.7% of Butte County's bridges have passed the 50-year mark

344 of the 437 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 31.8% 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 30% of the county's Poor-condition bridge traffic

COHASSET HWY over STATE ROUTE 99, built 1966, carries 27,008 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 27-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 90,044 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

4
1910s

20
1920s

38
1930s

54
1940s

32
1950s

55
1960s

115
1970s

47
1980s

25
1990s

16
2000s

18
2010s

8
2020s

5

What this shows Construction peaked in the 1960s, when 115 of the county's bridges still in the inventory were built, which is 26.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1958, 12 years older than the California average of 1970.

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

The 5 California counties nearest Butte County in number of bridges, with their condition splits. Its 6.2% Poor share is the 4th-lowest of these 6. Its average build year of 1958 against a peer-group mean of 1969 is 11 years older.

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

Bridge inventory size and condition shares for Butte County and the 5 California counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Tehama County	450	36.9%	56.2%	6.9%	1961
Imperial County	444	50.7%	40.5%	8.8%	1968
Butte County (this page)	437	31.8%	62%	6.2%	1958
Siskiyou County	421	39%	55.6%	5.5%	1971
Santa Barbara County	418	51.4%	42.8%	5.7%	1975
San Luis Obispo County	401	47.6%	46.6%	5.7%	1970

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

Similar inventory size

Nearest county inventories outside CA (437 bridges here).

Mercer County, PA · 438 bridges
Clay County, MO · 436 bridges
Licking County, OH · 439 bridges
Pinellas County, FL · 435 bridges

Similar average build year

Nearest mean year-built outside CA (1958 here).

Middlesex County, MA · avg 1958 · 818 bridges
Bucks County, PA · avg 1958 · 699 bridges
Cowley County, KS · avg 1958 · 337 bridges
Maui County, HI · avg 1958 · 185 bridges

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

All 437 Good 139 Fair 271 Poor 27

Fair-condition bridges (271)

Sort:

Butte County Bridge Snapshot

Condition distribution

Butte County's Poor-condition bridges carry 90,044 vehicle crossings a day

78.7% of Butte County's bridges have passed the 50-year mark

One structure carries 30% of the county's Poor-condition bridge traffic

How Butte 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 (271)

SR 70

DAYTON-DURHAM HWY

ALEXANDER AVE

STATE ROUTE 162

STATE ROUTE 70

STATE ROUTE 99 NB

ERICKSON RD

STATE ROUTE 70

STATE ROUTE 99 SB

STATE ROUTE 99 NB

STATE ROUTE 70

NELSON AVE

CROUCH AVE

HUMBOLDT ROAD

STATE ROUTE 99

BANGOR PARK RD

AQUAS FRIAS RD

MANGROVE AVE

SALEM STREET

MIDWAY ROAD

RICHVALE HWY

LUMPKIN ROAD

BANGOR HWY

HAMILTON NORD CANA

RICETON HWY

NELSON SHIPPEE RD

MUIR RD

STATE ROUTE 162

STATE ROUTE 32

STATE ROUTE 70

STATE ROUTE 149 SB

STATE ROUTE 99 NB

PENTZ ROAD

STATE ROUTE 162

NB 149 TO SB 99 RP

STATE ROUTE 99 NB

S149-E70 CONNECTOR

STATE ROUTE 70 WB

STATE ROUTE 70

STATE ROUTE 32

STATE ROUTE 70

STATE ROUTE 70

OROVILLE CHICO HWY

MIDWAY RD

MIDWAY ROAD

MIDWAY ROAD

LONE TREE ROAD

LARKIN RD

BIGGS AVE

AGUAS FRIAS ROAD

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