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.

When Grant County's bridges were built

306 bridges with a recorded construction year, grouped by decade

bridges

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).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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 Poor
Whatcom County 354 5.4%
Whitman County 347 3.5%
Kittitas County 308 10.4%
Spokane County 307 6.8%
Grant County (this page) 306 2.6%
Skagit County 254 2.4%

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).

Similar average build year

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

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

All bridges (306)

F ROAD NE

Good

Over: MAIN CANAL

F NE .43 mile N of 23, Grant, WA

Built 2008 Load: 41.5 t ADT: 18

SR 262

Good

Over: LAT. WG1J BLK 80

4.9 N JCT SR 26, Grant, WA

Built 1990 Load: 41.7 t ADT: 745

12 RD NE

Good

Over: EAST LOW CANAL

12 NE 2.2 E of J NE, Grant, WA

Built 2002 Load: 41.8 t ADT: 97

A-NW

Good

Over: W 22 CANAL

A NW 1.4 N of 9 NW, Grant, WA

Built 2003 Load: 41.8 t ADT: 467

Martin Road

Good

Over: Wasteway

Martin road at Adams, Grant, WA

Built 2017 Load: 42.8 t ADT: 188

SR 155

Good

Over: LOWER LEWIS CR

8.8 N JCT US 2, Grant, WA

Built 1949 Load: 43.5 t ADT: 959

Q RD

Good

Over: I-90

5.4 E JCT SR 17, Grant, WA

Built 1965 Load: 43.5 t ADT: 651

MAINTENANCE ROAD

Good

Over: WEST CANAL

WEST CANAL LATERAL W26C, Grant, WA

Built 1951 Load: 43.7 t ADT: 5

W-NE

Good

Over: BLACKROCK COULEE

W NE 0.2 S of 16, Grant, WA

Built 2003 Load: 43.7 t ADT: 235

HEADWORKS MAINTENA

Good

Over: CRAB CREEK SIPHON NO. 1

Crab Ck Siphon No. 1 Inle, Grant, WA

Built 1947 Load: 43.8 t ADT: 10

Canal Maintenance

Good

Over: East Low Canal - Crab Ck

Crab Ck Siphon No.1 Outle, Grant, WA

Built 1947 Load: 43.8 t ADT: 5

Canal Maintenance

Good

Over: East Low Canal - Brkn Rk

Broken Rock Siphon No.1 I, Grant, WA

Built 1947 Load: 43.8 t ADT: 2

Vantage Rd

Good

Over: FRENCHMAN SPRINGS

Vantage Rd 1.1 W Silica, Grant, WA

Built 1931 Load: 44.7 t ADT: 169

Adams road

Good

Over: Lateral. Block 73

Adams road at Martin, Grant, WA

Built 2017 Load: 45.0 t ADT: 247

WARDEN RD/ROAD U

Good

Over: I-90

9.5 E JCT SR 17, Grant, WA

Built 1966 Load: 46.3 t ADT: 913

SR 170

Good

Over: EAST LOW CANAL

2.4 E JCT SR 17, Grant, WA

Built 1980 Load: 46.3 t ADT: 2,802

POTATO HILL RD

Good

Over: I-90

1.5 E JCT SR 171, Grant, WA

Built 2006 Load: 47.2 t ADT: 4,037

WAHATIS PEAK ROAD

Good

Over: WAHLUKE BRANCH CANAL

NR MATTAWA WA, Grant, WA

Built 1967 Load: 48.3 t ADT: 3

SR 171

Good

Over: I-90

JCT I-90, Grant, WA

Built 2001 Load: 49.0 t ADT: 9,405

MAINTENANCE ROAD

Good

Over: WEST CANAL

Dry Coulee Siphon 2 Inlet, Grant, WA

Built 1946 Load: 50.7 t ADT: 5

Adams Rd

Good

Over: Lateral block 73

Adams at 11.5 NW, Grant, WA

Built 2017 Load: 52.8 t ADT: 589

11 N.W.

Good

Over: Wasteway

11 NW @ M NW, Grant, WA

Built 2017 Load: 53.8 t ADT: 232

S NE

Good

Over: Dry Coulee

S NE 1.0 S of 39 NE, Grant, WA

Built 2005 Load: 55.7 t ADT: 91

"39" Road NE

Good

Over: Field Runoff

39 NE .01 E of R NE, Grant, WA

Built 2010 Load: 56.1 t ADT: 49

US 2

Good

Over: DRY FALLS DAM

2.1 E DOUGLAS CO, Grant, WA

Built 1984 Load: 56.2 t ADT: 1,935

Maintenance Road

Good

Over: East Low Canal

Weber Branch Siphon, Grant, WA

Built 1950 Load: 56.8 t ADT: 1

East Low Canal

Good

Over: East Low Canal

Weber Coulee Siphon Outle, Grant, WA

Built 1950 Load: 56.8 t ADT: 1

Stratford Rd

Good

Over: Crab Creek

.25 S of Hwy 28, Grant, WA

Built 2017 Load: 59.6 t ADT: 778

MORGAN LAKE ROAD

Good

Over: POTHOLES CANAL

11.5 MI NNW OF OFFICE, Grant, WA

Built 2002 Load: 61.7 t ADT: 150

"R" Road NE

Good

Over: Field Runoff

R NE 0.5 North of 37, Grant, WA

Built 2010 Load: 64.5 t ADT: 156

BAIRD SPRINGS RD

Good

Over: Trinidad Creek

Baird Spring 1.7 N SR 28, Grant, WA

Built 2005 Load: 71.0 t ADT: 26

"R" Road NE

Good

Over: Field Runoff

R NE 0.1 North of 29 NE, Grant, WA

Built 2012 Load: 82.3 t ADT: 265

PENINSULA DRIVE

Good

Over: I-90

0.6 E JCT SR 171, Grant, WA

Built 2001 Load: 85.3 t ADT: 231

W-NE

Good

Over: NORTHUP CREEK

0.1S GR COULEE HILL RD, Grant, WA

Built 1985 Load: 88.8 t ADT: 56

SR 262

Good

Over: POTHOLES CANAL

17.5 N JCT SR 26, Grant, WA

Built 1949 Load: 89.8 t ADT: 1,559

Canal Maintenance

Good

Over: East Low Canal - Crab Ck

Crab Ck Siphon No.2 Inlet, Grant, WA

Built 1947 Load: 90.7 t ADT: 5

Canal Maintenance

Good

Over: East Low Canal - Crab Ck

Crab Ck Siphon No.2 Outle, Grant, WA

Built 1947 Load: 90.7 t ADT: 5

Canal Maintenance

Good

Over: East Low Canal - Brkn Rk

Broken Rock Siphon No.2 O, Grant, WA

Built 1947 Load: 90.7 t ADT: 1

MAINTENANCE ROAD

Good

Over: MAIN CANAL

MAIN CANAL 3.88, Grant, WA

Built 1977 Load: 91.5 t ADT: 10

40 RD NE

Good

Over: DRY CREEK

40 NE .2 W of S NE, Grant, WA

Built 1981 Load: 96.9 t ADT: 67

SAGEBRUSH FLATS RD

Good

Over: DRY WASH

0.1 E of JOHNSON RD, Grant, WA

Built 1993 Load: 96.9 t ADT: 670

SAGEBRUSH FLATS RD

Good

Over: DRY WASH

Sagebrush .1 W of City, Grant, WA

Built 1993 Load: 96.9 t ADT: 734

16 NE

Good

Over: Crab Creek

16 NE 4.0 W of Stratford, Grant, WA

Built 2010 Load: 96.9 t ADT: 157

R NE

Good

Over: Dry Wash

R NE .2 South of 34 NE, Grant, WA

Built 2013 Load: 96.9 t ADT: 262

MAINTENANCE ROAD

Good

Over: MAIN CANAL

MAIN CANAL 3.88, Grant, WA

Built 1977 Load: 97.8 t ADT: 10

MAINTENANCE ROAD

Good

Over: WEST CANAL

Frenchman Hills WW 5 mi, Grant, WA

Built 2008 Load: 99.9 t ADT: 10

East Low Canal

Good

Over: East Low Canal

Weber Branch Siphon, Grant, WA

Built 1950 Load: 99.9 t ADT: 1

East Low Canal

Good

Over: East Low Canal

Weber Coulee Siphon Inlet, Grant, WA

Built 1950 Load: 99.9 t ADT: 1

MI 2.8 THOMPSON

Poor

Over: ROCKY COULEE WASTEWAY

NR MOSES LAKE WA, Grant, WA

Built 1950 Load: 7.5 t ADT: 10

HANSEN RD

Poor

Over: I-90

22.8 E JCT SR 281, Grant, WA

Built 1958 Load: 14.3 t ADT: 4,835

Read our methodology - how this data is sourced, computed, and verified.

Related

Browse all → | Rankings →
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.