Total bridges
133
Public highway bridges in Mason County
County profile · official public datasets
Mason County, WA
133 public highway bridges tracked in the FHWA National Bridge Inventory: 53.4% rated Good, 42.1% Fair, 4.5% Poor.
- 133
- Public bridges
- 53.4%
- Good condition
- 4.5%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Mason County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 44%
- lowest Poor share in state
- 4.5%
- Poor-condition share
- 133
- public highway bridges
- 1975
- 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.
Mason County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Mason County ranks #17 of 39 Washington counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.5%). Mason County, Washington contains 133 public highway bridges. Roughly 53.4% are rated “Good,” 42.1% “Fair,” and 4.5% “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.
Good condition
53.4%
71 of 133 rated 7-9
Fair condition
42.1%
56 of 133 rated 5-6
Poor condition
4.5%
6 of 133 rated 4 or below
In-state Poor-share rank
#17 of 39
Among Washington counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 133 NBI-tracked bridges by lowest applicable component rating.
Good 53.4% (71)
Fair 42.1% (56)
Poor 4.5% (6)
Mason County's Poor-condition bridges carry 21,118 vehicle crossings a day
That is 5.1% of the county's reported daily bridge traffic on 4.5% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 3,520 crossings a day against 2,221 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 133 of 133 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
55.6% of Mason County's bridges have passed the 50-year mark
74 of the 133 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 53.4% 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 83.5% of the county's Poor-condition bridge traffic
US 101 over MATLOCK RD, built 1973, carries 17,635 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 6-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 21,118 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Mason County's bridges were built
133 bridges with a recorded construction year, grouped by decade
- 1910s 1
1910–1919
1 bridges
- 1920s 9
1920–1929
9 bridges
- 1930s 2
1930–1939
2 bridges
- 1940s 2
1940–1949
2 bridges
- 1950s
1950–1959
21 bridges
- 1960s
1960–1969
29 bridges
- 1970s
1970–1979
15 bridges
- 1980s 10
1980–1989
10 bridges
- 1990s
1990–1999
14 bridges
- 2000s
2000–2009
16 bridges
- 2010s 9
2010–2019
9 bridges
- 2020s 5
2020–2029
5 bridges
What this shows Construction peaked in the 1960s, when 29 of the county's bridges still in the inventory were built, which is 21.8% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1975) matches the Washington average (1975).
How Mason County compares with Washington's closest counties by inventory size
The 5 Washington counties nearest Mason County in number of bridges, with their condition splits. Its 4.5% Poor share is the 2nd-lowest of these 6. Its average build year of 1975 against a peer-group mean of 1974 is in line with the group.
Showing the 5 closest of 38 Washington counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Clallam County | 151 | 56.3% | 37.7% | 6% | 1979 |
| Chelan County | 149 | 57.7% | 34.2% | 8.1% | 1974 |
| Franklin County | 134 | 56% | 39.6% | 4.5% | 1970 |
| Mason County (this page) | 133 | 53.4% | 42.1% | 4.5% | 1975 |
| Pacific County | 120 | 56.7% | 37.5% | 5.8% | 1974 |
| Skamania County | 120 | 45.8% | 45% | 9.2% | 1974 |
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 Mason 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 Mason County, both outside Washington so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside WA (133 bridges here).
- Henry County, AL · 133 bridges
- Nevada County, AR · 133 bridges
- Gordon County, GA · 133 bridges
- East Feliciana County, LA · 133 bridges
Similar average build year
Nearest mean year-built outside WA (1975 here).
- San Bernardino County, CA · avg 1975 · 1,422 bridges
- Lane County, OR · avg 1975 · 1,010 bridges
- Fulton County, GA · avg 1975 · 775 bridges
- Westmoreland County, PA · avg 1975 · 620 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
All bridges (133)
23610
FairOver: CEDAR CREEK
NO DATA ENTERED, Mason, WA
Built 1959 ADT: 50
Arcadia Road
FairOver: BUR. NOR. RAILROAD
1.45 E JCT SR 3, Mason, WA
Built 1978 Load: 8.2 t ADT: 4,134
PARK ENTRANCE
FairOver: TWANOH CREEK
TWANOH STATE PARK, Mason, WA
Built 2000 Load: 13.6 t ADT: 125
SR 3
FairOver: MILL CREEK
0.9 N JCT US 101, Mason, WA
Built 1921 Load: 13.9 t ADT: 14,994
US 101
FairOver: HAMMA HAMMA RIVER
5.1 S JEFFERSON CO, Mason, WA
Built 1924 Load: 16.5 t ADT: 2,489
Arcadia Rd.
FairOver: MILL CREEK
4.72 E JCT SR 3, Mason, WA
Built 1971 Load: 17.2 t ADT: 879
North Shore Rd
FairOver: TAHUYA ESTUARY
0.14 S Belfair Tahuya rd, Mason, WA
Built 1961 Load: 18.1 t ADT: 513
Eich Road
FairOver: SKOOKUM CREEK
0.26 N JCT SR 108, Mason, WA
Built 1968 Load: 18.1 t ADT: 22
Bourgault Rd
FairOver: WEAVER CREEK
0.03 W JCT SR101, Mason, WA
Built 1966 Load: 19.0 t ADT: 73
Dewatto Holly rd
FairOver: DEWATTO RIVER
2.49 NE JCT Dewatto rd, Mason, WA
Built 1967 Load: 19.0 t ADT: 200
North Shore Rd
FairOver: RENDSLAND CREEK
4.48 W of Belfair Tahuya, Mason, WA
Built 1950 Load: 19.8 t ADT: 526
SR 3
FairOver: GOLDSBOROUGH CREEK
2.4 N JCT US 101, Mason, WA
Built 1923 Load: 20.1 t ADT: 16,880
SR 3
FairOver: SHERWOOD CREEK
20.5 N JCT US 101, Mason, WA
Built 1952 Load: 20.1 t ADT: 10,477
Deckerville Road
FairOver: DECKER CREEK
2.84 W JCT Matlock, Mason, WA
Built 1949 Load: 20.9 t ADT: 149
Beeville Loop Rd
FairOver: DRY BED CREEK
0.58 W JCT Beeville Rd, Mason, WA
Built 1954 Load: 20.9 t ADT: 86
Steelhead Drive So
FairOver: MISSION CREEK
0.04 W Mission Cr Rd, Mason, WA
Built 1990 Load: 20.9 t ADT: 950
NO DATA ENTERED
FairOver: CANYON RIVER
NO DATA ENTERED, Mason, WA
Built 1951 Load: 21.8 t ADT: 50
US 101
FairOver: LILLIWAUP R
12.6 S JEFFERSON CO, Mason, WA
Built 1925 Load: 22.4 t ADT: 3,048
SR 3
FairOver: CRANBERRY CREEK
8.6 N JCT US 101, Mason, WA
Built 1957 Load: 22.7 t ADT: 15,429
US 101
FairOver: WAKETICKEH CREEK
3.9 S JEFFERSON CO, Mason, WA
Built 1982 Load: 22.7 t ADT: 2,336
NO DATA ENTERED
FairOver: HAMMA HAMMA RIVER
NO DATA ENTERED, Mason, WA
Built 1950 Load: 22.7 t ADT: 30
US 101
FairOver: SKOKOMISH RIVER
1.8 S JCT SR 106, Mason, WA
Built 1932 Load: 23.6 t ADT: 7,382
SR 108
FairOver: SKOOKUM CREEK
2.5 E GRAYS HBR CO, Mason, WA
Built 1952 Load: 23.6 t ADT: 3,494
Agate Loop Rd
FairOver: CAMPBELL CREEK
0.48 N JCT CRESTVIEW DR, Mason, WA
Built 1950 Load: 23.6 t ADT: 257
US 101
FairOver: SUND CREEK
14.3 S JEFFERSON CO, Mason, WA
Built 1925 Load: 23.7 t ADT: 3,700
SR 302
FairOver: COULTER CR
1.3 E JCT SR 3, Mason, WA
Built 1956 Load: 24.5 t ADT: 4,208
SR 101
FairOver: CUSHMAN TAILRACE
19.9 S JEFFERSON CO, Mason, WA
Built 1930 Load: 24.9 t ADT: 7,100
SR 108
FairOver: SKOOKUM CREEK
6.9 E GRAYS HBR CO, Mason, WA
Built 1952 Load: 25.4 t ADT: 3,852
CO. RD. 90100
FairOver: DECKER CREEK
6.4 MI SO MATLOCK, Mason, WA
Built 1996 Load: 25.4 t ADT: 588
NO DATA ENTERED
FairOver: MID FORK SATSOP RIVER
NO DATA ENTERED, Mason, WA
Built 1967 Load: 26.3 t ADT: 50
NO DATA ENTERED
FairOver: WASHINGTON CREEK
NO DATA ENTERED, Mason, WA
Built 1965 Load: 26.3 t ADT: 10
SR 300
FairOver: UNION RIVER
2.9 E STATE PARK, Mason, WA
Built 1960 Load: 27.2 t ADT: 11,840
SR 300
FairOver: MISSION CREEK
0.3 E STATE PARK, Mason, WA
Built 1963 Load: 27.2 t ADT: 7,194
Mission Creek Road
FairOver: BIG MISSION CREEK
0.79 N JCT SR 300, Mason, WA
Built 1968 Load: 27.2 t ADT: 671
NO DATA ENTERED
FairOver: N FK SKOKOMISH RIVER
NO DATA ENTERED, Mason, WA
Built 1929 Load: 29.1 t ADT: 50
Mary M Knight Rd
FairOver: DRY CREEK
0.15 W of MatlockBradyRD, Mason, WA
Built 1970 Load: 29.9 t ADT: 148
NO DATA ENTERED
FairOver: S FK SKOKOMISH RIVER
NO DATA ENTERED, Mason, WA
Built 1963 Load: 30.0 t ADT: 50
NO DATA ENTERED
FairOver: BOULDER CREEK
NO DATA ENTERED, Mason, WA
Built 1965 Load: 31.8 t ADT: 25
SR 3
FairOver: JOHNS CREEK
6.6 N JCT US 101, Mason, WA
Built 1948 Load: 33.7 t ADT: 15,367
US 101
FairOver: CREEK/RR/STREET
3.1 S JCT SR 102, Mason, WA
Built 1973 Load: 34.3 t ADT: 17,635
US 101
FairOver: KENNEDY CREEK
2.7 S JCT SR 108, Mason, WA
Built 1960 Load: 35.0 t ADT: 12,897
US 101
FairOver: KENNEDY CREEK
2.7 S JCT SR 108, Mason, WA
Built 1960 Load: 35.0 t ADT: 12,897
US 101
FairOver: SKOOKUM CR NP RY
0.3 S JCT SR 108, Mason, WA
Built 1962 Load: 35.4 t ADT: 12,553
US 101
FairOver: SKOOKUM CR NP RY
0.3 S JCT SR 108, Mason, WA
Built 1962 Load: 35.4 t ADT: 12,553
SR 119
FairOver: BIG CREEK
9.4 N JCT SR 101, Mason, WA
Built 1960 Load: 36.0 t ADT: 513
US 101
FairOver: SR 3
5.7 S JCT SR 102, Mason, WA
Built 1972 Load: 37.2 t ADT: 16,537
Old Olympic Highwa
FairOver: KENNEDY CREEK
0.40 S JCT SR 101, Mason, WA
Built 1917 Load: 37.2 t ADT: 72
NO DATA ENTERED
FairOver: JEFFERSON CREEK
NO DATA ENTERED, Mason, WA
Built 1957 Load: 38.1 t ADT: 50
US 101
FairOver: JORSTED CREEK
6.8 S JEFFERSON CO, Mason, WA
Built 1985 Load: 39.9 t ADT: 2,489
NO DATA ENTERED
FairOver: CHURCH CREEK
NO DATA ENTERED, Mason, WA
Built 1965 Load: 44.5 t ADT: 50
Read our methodology - how this data is sourced, computed, and verified.
Related
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.