County profile · official public datasets

Mono County, CA

49 public highway bridges tracked in the FHWA National Bridge Inventory: 63.3% rated Good, 24.5% Fair, 12.2% Poor.

49
Public bridges: 63.3%
Good condition: 12.2%
Poor condition

The verdict

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

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

52nd
of 58 on Poor share: 12.2%
Poor-condition share: 49
public highway bridges: 1970
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.

Mono County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Mono County ranks #52 of 58 California counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 12.2%). Mono County, California contains 49 public highway bridges. Roughly 63.3% are rated “Good,” 24.5% “Fair,” and 12.2% “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

Public highway bridges in Mono County

Good condition

63.3%

31 of 49 rated 7-9

Fair condition

24.5%

12 of 49 rated 5-6

Poor condition

12.2%

6 of 49 rated 4 or below

In-state Poor-share rank

#52 of 58

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

Condition distribution

Share of 49 NBI-tracked bridges by lowest applicable component rating.

Good

63.3% (31)

Fair

24.5% (12)

Poor

12.2% (6)

Mono County's Poor-condition bridges carry 436 vehicle crossings a day

That is 0.3% of the county's reported daily bridge traffic on 12.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 73 crossings a day against 3,878 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 49 of 49 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

57.1% of Mono County's bridges have passed the 50-year mark

28 of the 49 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 63.3% 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 23.9% of the county's Poor-condition bridge traffic

LARSON LANE over WEST WALKER RIVER, built 1952, carries 104 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 6-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 436 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

1
1930s

5
1940s

2
1950s

6
1960s

11
1970s

7
1980s

6
1990s

5
2000s

5
2010s

1

What this shows Construction peaked in the 1960s, when 11 of the county's bridges still in the inventory were built, which is 22.4% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1970) matches the California average (1970).

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

The 5 California counties nearest Mono County in number of bridges, with their condition splits. Its 12.2% Poor share is the 5th-lowest of these 6. Its average build year of 1970 against a peer-group mean of 1969 is in line with the group.

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

Bridge inventory size and condition shares for Mono County and the 5 California counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
San Benito County	76	46.1%	43.4%	10.5%	1971
Inyo County	66	63.6%	31.8%	4.5%	1972
Sierra County	65	40%	52.3%	7.7%	1972
Amador County	61	37.7%	37.7%	24.6%	1966
Mono County (this page)	49	63.3%	24.5%	12.2%	1970
Alpine County	32	34.4%	59.4%	6.3%	1964

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

Similar inventory size

Nearest county inventories outside CA (49 bridges here).

Yuma County, CO · 49 bridges
Calhoun County, FL · 49 bridges
Crawford County, GA · 49 bridges
Johnson County, GA · 49 bridges

Similar average build year

Nearest mean year-built outside CA (1970 here).

Hamilton County, OH · avg 1970 · 783 bridges
Yavapai County, AZ · avg 1970 · 543 bridges
Garfield County, OK · avg 1970 · 504 bridges
Somerset County, NJ · avg 1970 · 397 bridges

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

All 49 Good 31 Fair 12 Poor 6

All bridges (49)

Sort:

BUCKEYE-ROBINSON

Fair

Over: ROBINSON CREEK

NO DATA ENTERED, Mono, CA

Built 1983 Load: 19.1 t ADT: 90

BUCKEYE CAMPGROUND

Fair

Over: BUCKEYE CREEK

NO DATA ENTERED, Mono, CA

Built 1978 Load: 23.7 t ADT: 150

US HIGHWAY 395 NB

Fair

Over: STATE ROUTE 203

09-MNO-395-R25.73, Mono, CA

Built 1969 Load: 29.2 t ADT: 4,650

US HIGHWAY 395 SB

Fair

Over: STATE ROUTE 203

09-MNO-395-R25.73, Mono, CA

Built 1969 Load: 29.8 t ADT: 9,500

32143

Fair

Over: GREEN CREEK

NO DATA ENTERED, Mono, CA

Built 1961 Load: 30.5 t ADT: 30

STATE ROUTE 158

Fair

Over: RUSH CREEK

09-MNO-158-5.90, Mono, CA

Built 1963 Load: 32.4 t ADT: 3,050

STATE ROUTE 108

Fair

Over: SARDINE CREEK

09-MNO-108-3.05, Mono, CA

Built 2002 Load: 32.4 t ADT: 1,910

SOUTH LANDING ROAD

Fair

Over: US HIGHWAY 395

09-MNO-395-R13.93, Mono, CA

Built 1970 Load: 33.7 t ADT: 450

STATE ROUTE 120

Fair

Over: HILLSIDE

09-MNO-120-R3.71, Mono, CA

Built 1966 Load: 57.0 t ADT: 5,320

EASTSIDE LANE

Fair

Over: WEST WALKER RIVER

0.1 MI N RTE 395 JCT, Mono, CA

Built 1952 Load: 59.3 t ADT: 826

EASTSIDE LANE

Fair

Over: IRRIGATION CANAL

0.2 MI N RTE 395 JCT, Mono, CA

Built 1978 Load: 64.2 t ADT: 826

U.S. HIGHWAY 395

Fair

Over: CROOKED CREEK

09-MNO-395-R12.48, Mono, CA

Mono County Bridge Snapshot

Condition distribution

Mono County's Poor-condition bridges carry 436 vehicle crossings a day

57.1% of Mono County's bridges have passed the 50-year mark

One structure carries 23.9% of the county's Poor-condition bridge traffic

How Mono 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 (49)

BUCKEYE-ROBINSON

BUCKEYE CAMPGROUND

US HIGHWAY 395 NB

US HIGHWAY 395 SB

32143

STATE ROUTE 158

STATE ROUTE 108

SOUTH LANDING ROAD

STATE ROUTE 120

EASTSIDE LANE

EASTSIDE LANE

U.S. HIGHWAY 395

NO DATA ENTERED

NO DATA ENTERED

LARSON LANE

GREEN LAKE RD

STATE ROUTE 108

TOPAZ LANE

01N04A

U.S. HIGHWAY 395

U.S. HIGHWAY 395

U.S. HIGHWAY 395

U.S. HIGHWAY 395

LOWER ROCK CRK RD

U.S. HIGHWAY 395

TWIN LAKES CAMP RD

U.S. HIGHWAY 395

U.S. HIGHWAY 395

U.S. HIGHWAY 395

U.S. HIGHWAY 395

U.S. HIGHWAY 395

U.S. HIGHWAY 395

US HIGHWAY 395 SB

US HIGHWAY 395 NB

U.S. HIGHWAY 6

STATE ROUTE 108

TWIN LAKES ROAD

US HIGHWAY 395 SB

US HIGHWAY 395 NB

BENTON CROSSING RD

U.S. HIGHWAY 395

STATE ROUTE 182

STATE ROUTE 108

CUNNINGHAM LANE

GREEN CREEK ROAD

32017

FOREST ROAD 62

LARSON LANE

STOCK DR

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