County profile · official public datasets

Washington County, ID

80 public highway bridges tracked in the FHWA National Bridge Inventory: 32.5% rated Good, 61.3% Fair, 6.3% Poor.

80
Public bridges: 32.5%
Good condition: 6.3%
Poor condition

The verdict

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

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

30th
of 44 on Poor share: 6.3%
Poor-condition share: 80
public highway bridges: 1979
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.

Washington County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Washington County ranks #30 of 44 Idaho counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.3%). Washington County, Idaho contains 80 public highway bridges. Roughly 32.5% are rated “Good,” 61.3% “Fair,” and 6.3% “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

Public highway bridges in Washington County

Good condition

32.5%

26 of 80 rated 7-9

Fair condition

61.3%

49 of 80 rated 5-6

Poor condition

6.3%

5 of 80 rated 4 or below

In-state Poor-share rank

#30 of 44

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

Condition distribution

Share of 80 NBI-tracked bridges by lowest applicable component rating.

Good

32.5% (26)

Fair

61.3% (49)

Poor

6.3% (5)

Washington County's Poor-condition bridges carry 750 vehicle crossings a day

That is 0.9% of the county's reported daily bridge traffic on 6.3% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 150 crossings a day against 1,400 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 80 of 80 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

42.5% of Washington County's bridges have passed the 50-year mark

34 of the 80 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 32.5% 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 64% of the county's Poor-condition bridge traffic

STC 8217;COVE ROAD over WEISER RIVER, built 1917, carries 480 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 5-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 750 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

3
1930s

4
1950s

10
1960s

9
1970s

12
1980s

6
1990s

17
2000s

11
2010s

6
2020s

2

What this shows Construction peaked in the 1990s, when 17 of the county's bridges still in the inventory were built, which is 21.3% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1979) matches the Idaho average (1979).

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

The 5 Idaho counties nearest Washington County in number of bridges, with their condition splits. Its 6.3% Poor share is the 3rd-lowest of these 6. Its average build year of 1979 against a peer-group mean of 1976 is in line with the group.

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

Bridge inventory size and condition shares for Washington County and the 5 Idaho counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Boise County	88	46.6%	47.7%	5.7%	1978
Adams County	87	32.2%	57.5%	10.3%	1975
Boundary County	83	32.5%	57.8%	9.6%	1982
Gooding County	80	16.3%	76.3%	7.5%	1965
Madison County	80	30%	70%	0%	1981
Washington County (this page)	80	32.5%	61.3%	6.3%	1979

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

Similar inventory size

Nearest county inventories outside ID (80 bridges here).

Moffat County, CO · 80 bridges
Burke County, GA · 80 bridges
Todd County, KY · 80 bridges
Iberville County, LA · 80 bridges

Similar average build year

Nearest mean year-built outside ID (1979 here).

Pima County, AZ · avg 1979 · 1,150 bridges
Jefferson County, KY · avg 1979 · 662 bridges
Spartanburg County, SC · avg 1979 · 638 bridges
McPherson County, KS · avg 1979 · 586 bridges

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

All 80 Good 26 Fair 49 Poor 5

Fair-condition bridges (49)

Sort:

Washington County Bridge Snapshot

Condition distribution

Washington County's Poor-condition bridges carry 750 vehicle crossings a day

42.5% of Washington County's bridges have passed the 50-year mark

One structure carries 64% of the county's Poor-condition bridge traffic

How Washington 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

Fair-condition bridges (49)

ADAMS CK RD 50025

S. CRANE CREEK RD

ROCK CREEK ROAD

STC 3879;BURTON LN

CRANE CRK RES RD

RUSH CREEK ROAD

STC3008;OLDS FERRY

STC8215;WEISER RVR

OLD HWY ROAD

STC8217;COVE ROAD

WARD ROAD NORTH

LOWER CRANE ROAD

WEISER RIVER ROAD

SH 71

US 95

JONES ROAD

STC8215;WEISER RVR

SH 71

FARM TO MARKET RD

WARD ROAD SOUTH

THOMASON LANE

US 95

STC 8216;E 9TH ST

WEISER RIVER ROAD

WIGGINS ROAD

N. CRANE ROAD

S. CRANE CREEK RD

COUNTY ROAD

W. COMMERCIAL ST.

GLADHART

SH 71

US 95

US 95

JACKSON ROAD

BIG FLAT ROAD

STC3878;OLD HWY 95

SAND ROAD

US 95

US 95

US 95

N CRANE ROAD

US 95

TOWELL ROAD

SALUBRIA ROAD

STC 3727;SHOE PEG

COW CREEK ROAD

SHOEPEG ROAD

STC 3881;STATE ST

BIG FLAT ROAD

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