County profile · official public datasets

Grant County, WA

306 public highway bridges tracked in the FHWA National Bridge Inventory: 63.7% rated Good, 33.7% Fair, 2.6% Poor.

306
Public bridges: 63.7%
Good condition: 2.6%
Poor condition

The verdict

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

Grant County posts a top-quartile lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 15%
lowest Poor share in state: 2.6%
Poor-condition share: 306
public highway bridges: 1973
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.

Grant County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Grant County ranks #6 of 39 Washington counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.6%). Grant County, Washington contains 306 public highway bridges. Roughly 63.7% are rated “Good,” 33.7% “Fair,” and 2.6% “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

306

Public highway bridges in Grant County

Good condition

63.7%

195 of 306 rated 7-9

Fair condition

33.7%

103 of 306 rated 5-6

Poor condition

2.6%

8 of 306 rated 4 or below

In-state Poor-share rank

#6 of 39

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

Condition distribution

Share of 306 NBI-tracked bridges by lowest applicable component rating.

Good

63.7% (195)

Fair

33.7% (103)

Poor

2.6% (8)

Grant County's Poor-condition bridges carry 20,503 vehicle crossings a day

That is 4.4% of the county's reported daily bridge traffic on 2.6% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 2,563 crossings a day against 957 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 306 of 306 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

56.5% of Grant County's bridges have passed the 50-year mark

173 of the 306 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 63.7% 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 26.4% of the county's Poor-condition bridge traffic

I-90 over WEST CANAL, built 1964, carries 5,419 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 8-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 20,503 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1910s

4
1920s

1
1930s

6
1940s

25
1950s

90
1960s

40
1970s

15
1980s

34
1990s

42
2000s

30
2010s

19

What this shows Construction peaked in the 1950s, when 90 of the county's bridges still in the inventory were built, which is 29.4% of those with a recorded year. That cohort is now 65 to 74 years old in the 2024 inventory. Its average build year (1973) matches the Washington average (1975).

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

The 5 Washington counties nearest Grant County in number of bridges, with their condition splits. Its 2.6% Poor share is the 2nd-lowest of these 6. Its average build year of 1973 against a peer-group mean of 1973 is in line with the group.

Showing the 5 closest of 38 Washington counties eligible for comparison.

Bridge inventory size and condition shares for Grant County and the 5 Washington counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Whatcom County	354	44.1%	50.6%	5.4%	1970
Whitman County	347	52.2%	44.4%	3.5%	1974
Kittitas County	308	39%	50.6%	10.4%	1973
Spokane County	307	51.1%	42%	6.8%	1978
Grant County (this page)	306	63.7%	33.7%	2.6%	1973
Skagit County	254	38.2%	59.4%	2.4%	1972

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

Similar inventory size

Nearest county inventories outside WA (306 bridges here).

La Paz County, AZ · 306 bridges
Adair County, IA · 306 bridges
Greene County, PA · 306 bridges
Greene County, TN · 306 bridges

Similar average build year

Nearest mean year-built outside WA (1973 here).

Jefferson County, AL · avg 1973 · 1,068 bridges
Erie County, NY · avg 1973 · 906 bridges
Davidson County, TN · avg 1973 · 832 bridges
Lancaster County, PA · avg 1973 · 801 bridges

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

All 306 Good 195 Fair 103 Poor 8

Good-condition bridges (195)

Sort:

Grant County Bridge Snapshot

Condition distribution

Grant County's Poor-condition bridges carry 20,503 vehicle crossings a day

56.5% of Grant County's bridges have passed the 50-year mark

One structure carries 26.4% of the county's Poor-condition bridge traffic

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

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Good-condition bridges (195)

0 SW

7 RD NW

L ROAD SW

24 ROAD SW

31 NE

L RD SW

20 ROAD NW

M RD SW

Q RD NE

FARM ACCESS

3 SE

0.5 SW ROAD

18 NE

MAINTENANCE ROAD

U.7

S RD NE

P NW

4 SE

I RD SW

R RD SE

WHITETRAIL RD

J RD SW

Farm Access/Maint.

Farm Access

Cresent Bar Rd

2 RD SE

W RD SE

R RD NW

MONUMENT HILL ROAD

G RD SW

W NW

MAINTENANCE ROAD

Wheeler Rd

Vantage Rd

SR 243

Cannawai Valley Rd

Q - NW

I-90

I-90

S NW

9-NW

Sand Dunes Rd

I-90

I-90

SR 28

US 2

3 RD NW

F ROAD NE

SR 262

12 RD NE

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