County profile · official public datasets

Jerome County, ID

110 public highway bridges tracked in the FHWA National Bridge Inventory: 10% rated Good, 80.9% Fair, 9.1% Poor.

110
Public bridges: 10%
Good condition: 9.1%
Poor condition

The verdict

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

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

37th
of 44 on Poor share: 9.1%
Poor-condition share: 110
public highway bridges: 1974
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.

Jerome County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Jerome County ranks #37 of 44 Idaho counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 9.1%). Jerome County, Idaho contains 110 public highway bridges. Roughly 10% are rated “Good,” 80.9% “Fair,” and 9.1% “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

110

Public highway bridges in Jerome County

Good condition

10%

11 of 110 rated 7-9

Fair condition

80.9%

89 of 110 rated 5-6

Poor condition

9.1%

10 of 110 rated 4 or below

In-state Poor-share rank

#37 of 44

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

Condition distribution

Share of 110 NBI-tracked bridges by lowest applicable component rating.

Good

10% (11)

Fair

80.9% (89)

Poor

9.1% (10)

Jerome County's Poor-condition bridges carry 11,760 vehicle crossings a day

That is 2.6% of the county's reported daily bridge traffic on 9.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,176 crossings a day against 3,705 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 110 of 110 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

63.6% of Jerome County's bridges have passed the 50-year mark

70 of the 110 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 10% 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 82.9% of the county's Poor-condition bridge traffic

RIDGEWAY ROAD over C CANAL, built 1963, carries 9,750 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 10-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 11,760 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

2
1930s

4
1950s

5
1960s

48
1970s

18
1980s

12
1990s

6
2000s

9
2010s

4
2020s

2

What this shows Construction peaked in the 1960s, when 48 of the county's bridges still in the inventory were built, which is 43.6% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1974, 5 years older than the Idaho average of 1979.

How Jerome County compares with Idaho's closest counties by inventory size

The 5 Idaho counties nearest Jerome County in number of bridges, with their condition splits. Its 9.1% Poor share is the 6th-lowest of these 6. Its average build year of 1974 against a peer-group mean of 1982 is 8 years older.

Showing the 5 closest of 43 Idaho counties eligible for comparison.

Bridge inventory size and condition shares for Jerome County and the 5 Idaho counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Cassia County	116	15.5%	84.5%	0%	1984
Latah County	115	35.7%	64.3%	0%	1978
Lemhi County	112	53.6%	40.2%	6.3%	1988
Jerome County (this page)	110	10%	80.9%	9.1%	1974
Bonner County	104	37.5%	53.8%	8.7%	1983
Elmore County	97	25.8%	70.1%	4.1%	1977

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

Similar inventory size

Nearest county inventories outside ID (110 bridges here).

Lincoln County, AR · 110 bridges
Sharp County, AR · 110 bridges
Comanche County, KS · 110 bridges
Powell County, KY · 110 bridges

Similar average build year

Nearest mean year-built outside ID (1974 here).

Knox County, TN · avg 1974 · 588 bridges
Summit County, OH · avg 1974 · 563 bridges
Onondaga County, NY · avg 1974 · 472 bridges
Orange County, NY · avg 1974 · 472 bridges

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

All 110 Good 11 Fair 89 Poor 10

All bridges (110)

Sort:

Jerome County Bridge Snapshot

Condition distribution

Jerome County's Poor-condition bridges carry 11,760 vehicle crossings a day

63.6% of Jerome County's bridges have passed the 50-year mark

One structure carries 82.9% of the county's Poor-condition bridge traffic

How Jerome County compares with Idaho'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 (110)

2407: WENDELL SHEE

1700 EAST ROAD

300 EAST ROAD

100 SOUTH ROAD

100 WEST ROAD

VALLEY ROAD

EDEN ROAD

STC2757;NORTH ROAD

2000 EAST ROAD

2300 EAST ROAD

600 EAST ROAD

990 SOUTH ROAD

2100 EAST ROAD

400 NORTH ROAD

EAST ROAD

100 WEST ROAD

400 EAST ROAD

1100 SOUTH ROAD

500 EAST ROAD

400 NORTH ROAD

1300 SOUTH ROAD

100 EAST ROAD

2200 EAST ROAD

500 NORTH ROAD

STC2755;200 NORTH

800 EAST ROAD

300 EAST ROAD

300 EAST ROAD

500 NORTH ROAD

200 NORTH ROAD

990 SOUTH ROAD

SH 25

1010 SOUTH ROAD

CO. RD.;OLD US 93

I 84 EBL

N 300 W

I 84 WBL

I 84 WBL

STC2765;BOB BARTON

I 84 EBL

400 EAST ROAD

CO. RD.;OLD US 93

STC2768;MILNER RD.

STC2768;MILNER RD.

990 SOUTH ROAD

STC2755;200 NORTH

800 EAST ROAD

EDEN ROAD (1600 E)

SH 25; RIDGEWAY RD

I 84 EBL

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