County profile · official public datasets

Elmore County, ID

97 public highway bridges tracked in the FHWA National Bridge Inventory: 25.8% rated Good, 70.1% Fair, 4.1% Poor.

97
Public bridges: 25.8%
Good condition: 4.1%
Poor condition

The verdict

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

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

Top 43%
lowest Poor share in state: 4.1%
Poor-condition share: 97
public highway bridges: 1977
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.

Elmore County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Elmore County ranks #19 of 44 Idaho counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.1%). Elmore County, Idaho contains 97 public highway bridges. Roughly 25.8% are rated “Good,” 70.1% “Fair,” and 4.1% “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

Public highway bridges in Elmore County

Good condition

25.8%

25 of 97 rated 7-9

Fair condition

70.1%

68 of 97 rated 5-6

Poor condition

4.1%

4 of 97 rated 4 or below

In-state Poor-share rank

#19 of 44

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

Condition distribution

Share of 97 NBI-tracked bridges by lowest applicable component rating.

Good

25.8% (25)

Fair

70.1% (68)

Poor

4.1% (4)

Elmore County's Poor-condition bridges carry 130 vehicle crossings a day

That is 0.1% of the county's reported daily bridge traffic on 4.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 33 crossings a day against 753 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 97 of 97 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

58.8% of Elmore County's bridges have passed the 50-year mark

57 of the 97 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 25.8% 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 38.5% of the county's Poor-condition bridge traffic

FALL CK.-ROCKY BAR over EAST FORK FALL CREEK, built 2013, carries 50 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 4-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 130 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1950s

18
1960s

18
1970s

34
1980s

7
1990s

5
2000s

3
2010s

11
2020s

1

What this shows Construction peaked in the 1970s, when 34 of the county's bridges still in the inventory were built, which is 35.1% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1977) matches the Idaho average (1979).

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

The 5 Idaho counties nearest Elmore County in number of bridges, with their condition splits. Its 4.1% Poor share is the 2nd-lowest of these 6. Its average build year of 1977 against a peer-group mean of 1977 is in line with the group.

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

Bridge inventory size and condition shares for Elmore County and the 5 Idaho counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Bonner County	104	37.5%	53.8%	8.7%	1983
Elmore County (this page)	97	25.8%	70.1%	4.1%	1977
Blaine County	96	25%	71.9%	3.1%	1978
Boise County	88	46.6%	47.7%	5.7%	1978
Clearwater County	88	43.2%	51.1%	5.7%	1973
Adams County	87	32.2%	57.5%	10.3%	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 Elmore 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 Elmore County, both outside Idaho so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside ID (97 bridges here).

Forsyth County, GA · 97 bridges
Mason County, KY · 97 bridges
Swift County, MN · 97 bridges
Madison County, MT · 97 bridges

Similar average build year

Nearest mean year-built outside ID (1977 here).

San Diego County, CA · avg 1977 · 1,632 bridges
King County, WA · avg 1977 · 1,238 bridges
Riverside County, CA · avg 1977 · 1,117 bridges
Shelby County, TN · avg 1977 · 1,077 bridges

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

All 97 Good 25 Fair 68 Poor 4

All bridges (97)

Sort:

Elmore County Bridge Snapshot

Condition distribution

Elmore County's Poor-condition bridges carry 130 vehicle crossings a day

58.8% of Elmore County's bridges have passed the 50-year mark

One structure carries 38.5% of the county's Poor-condition bridge traffic

How Elmore 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 (97)

DANSKIN ROAD

MCCOY BRIDGE RD

MORROW RESERVOIR R

STC 3809;MIDDLE FK

FH 205;CHINA BASIN

STC 3809;MIDDLE FK

QUEENS RIVER ROAD

STC 3810;GRAVEL RD

STC 3809;MIDDLE FK

SMITH CREEK ROAD

SMITH CREEK ROAD

BARBER FLAT ROAD

BENNETT RD

STC 3809;MIDDLE FK

I 84 WBL

I 84 EBL

WAGONTOWN ROAD

STC 3811;FH 61 RD.

FALL CK.-ROCKY BAR

NEAL ROAD

E.FK.-FLY CK. ROAD

I 84 EBL

I 84 WBL

STC3816;OLD HWY 30

YUBA RIVER ROAD

HILL ROAD

MONTGOMERY RD

MULE GULCH ROAD

I 84B

I 84 EBL

EIGHTEENTH STREET

SMITH CREEK ROAD

DITTO CREEK ROAD

I 84B

I 84B ;FIRST AVE

BOISE AVE

CANYON CREEK ROAD

I 84 WBL

I 84 EBL

I 84 WBL

I 84 EBL

I 84 WBL

STC 3811;PINE RD

STC 3811;FH61 RD

OLD HWY 30

STC3813;OLD ORE TR

STC3814;OLD HWY 30

STC 3809;MIDDLE FK

I 84 WBL

S3802;SLICK RANCH

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