Total bridges
205
Public highway bridges in Thurston County
County profile · official public datasets
Thurston County, WA
205 public highway bridges tracked in the FHWA National Bridge Inventory: 59.5% rated Good, 39.5% Fair, 1% Poor.
- 205
- Public bridges
- 59.5%
- Good condition
- 1%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Thurston County posts a top-10% lowest Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 10%
- lowest Poor share in state
- 1%
- Poor-condition share
- 205
- 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.
Thurston County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Thurston County ranks #4 of 39 Washington counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 1%). Thurston County, Washington contains 205 public highway bridges. Roughly 59.5% are rated “Good,” 39.5% “Fair,” and 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.
Good condition
59.5%
122 of 205 rated 7-9
Fair condition
39.5%
81 of 205 rated 5-6
Poor condition
1%
2 of 205 rated 4 or below
In-state Poor-share rank
#4 of 39
Among Washington counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 205 NBI-tracked bridges by lowest applicable component rating.
Good 59.5% (122)
Fair 39.5% (81)
Poor 1% (2)
Thurston County's Poor-condition bridges carry 20,568 vehicle crossings a day
That is 0.8% of the county's reported daily bridge traffic on 1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 10,284 crossings a day against 10,482 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 205 of 205 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
41% of Thurston County's bridges have passed the 50-year mark
84 of the 205 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 59.5% 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 66.9% of the county's Poor-condition bridge traffic
CAPITOL BLVD over I-5 RAMP, built 1956, carries 13,767 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 2-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 20,568 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Thurston County's bridges were built
205 bridges with a recorded construction year, grouped by decade
- 1910s 1
1910–1919
1 bridges
- 1920s 7
1920–1929
7 bridges
- 1930s 5
1930–1939
5 bridges
- 1940s 3
1940–1949
3 bridges
- 1950s
1950–1959
34 bridges
- 1960s
1960–1969
24 bridges
- 1970s
1970–1979
20 bridges
- 1980s
1980–1989
42 bridges
- 1990s
1990–1999
28 bridges
- 2000s
2000–2009
18 bridges
- 2010s
2010–2019
17 bridges
- 2020s 6
2020–2029
6 bridges
What this shows Construction peaked in the 1980s, when 42 of the county's bridges still in the inventory were built, which is 20.5% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1979) matches the Washington average (1975).
How Thurston County compares with Washington's closest counties by inventory size
The 5 Washington counties nearest Thurston County in number of bridges, with their condition splits. Its 1% Poor share is the 1st-lowest of these 6. Its average build year of 1979 against a peer-group mean of 1972 is 7 years newer.
Showing the 5 closest of 38 Washington counties eligible for comparison.
| County | Bridges | Good | Fair | Poor | Avg. built |
|---|---|---|---|---|---|
| Clark County | 218 | 55% | 40.8% | 4.1% | 1979 |
| Thurston County (this page) | 205 | 59.5% | 39.5% | 1% | 1979 |
| Walla Walla County | 195 | 64.1% | 27.2% | 8.7% | 1980 |
| Adams County | 187 | 35.3% | 54.5% | 10.2% | 1961 |
| Lincoln County | 180 | 56.7% | 37.2% | 6.1% | 1965 |
| Benton County | 167 | 58.7% | 35.9% | 5.4% | 1977 |
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 Thurston 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 Thurston County, both outside Washington so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside WA (205 bridges here).
- Geneva County, AL · 205 bridges
- Russell County, AL · 205 bridges
- Wilson County, KS · 205 bridges
- Bell County, KY · 205 bridges
Similar average build year
Nearest mean year-built outside WA (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.
Fair-condition bridges (81)
US 101
FairOver: PERCIVAL CR & BNRR
4.5 S JCT SR 8, Thurston, WA
Built 1995 Load: 40.8 t ADT: 37,225
CASE ROAD SW
FairOver: SCATTER CREEK
0.7 m N of 183rd Ave SW, Thurston, WA
Built 1965 Load: 40.8 t ADT: 2,751
SR 507
FairOver: DESCHUTES RIVER
15.0 N LEWIS CO, Thurston, WA
Built 1943 Load: 41.7 t ADT: 5,063
INDEPENDENCE ROAD
FairOver: CHEHALIS RIVER
Over the Chehalis River, Thurston, WA
Built 1976 Load: 42.6 t ADT: 1,409
LITTLEROCK RD.
FairOver: CREEK
3.9 N SR 12, Thurston, WA
Built 1951 Load: 43.5 t ADT: 3,164
OLD HWY 99 SW
FairOver: SCATTER CREEK
WEST OF TENINO NEAR TRAC, Thurston, WA
Built 1923 Load: 44.4 t ADT: 5,042
MARTIN WAY EAST
FairOver: MC ALLISTER CREEK
.23 m SW of Nisqually Cu, Thurston, WA
Built 2000 Load: 44.4 t ADT: 17,895
128TH AVE SW
FairOver: BLACK RIVER
.23 W OF LITTLEROCK RD, Thurston, WA
Built 1968 Load: 45.4 t ADT: 3,047
183RD SW
FairOver: SCATTER CREEK
0.5 m W of Sargent Rd Int, Thurston, WA
Built 1949 Load: 45.4 t ADT: 2,813
183RD SW
FairOver: OVERFLOW CHANNEL
0.65 m E of Moon Rd, Thurston, WA
Built 1924 Load: 46.3 t ADT: 301
SARGENT ROAD
FairOver: SCATTER CREEK
.63 m N of 183rd, Thurston, WA
Built 1984 Load: 46.3 t ADT: 2,812
EVERGREEN PARKWAY
FairOver: MUD BAY ROAD
0.2 N JCT US 101, Thurston, WA
Built 1975 Load: 47.2 t ADT: 6,090
GOEBEL RD SE
FairOver: SKOOKUMCHUCK RIVER
0.11 m N Skookumchuck Rd, Thurston, WA
Built 1982 Load: 50.8 t ADT: 27
THOMPSON CREEK RD.
FairOver: THOMPSON CREEK
0.12 m S Skookumchuck Rd, Thurston, WA
Built 1987 Load: 51.7 t ADT: 89
110TH AVE SW
FairOver: BLACK RIVER
0.75 W Littlerock Rd, Thurston, WA
Built 1986 Load: 52.6 t ADT: 2,339
GIBSON ROAD SW
FairOver: SCATTER CREEK
0.14 mile North of Hwy 99, Thurston, WA
Built 1967 Load: 52.6 t ADT: 535
US 101
FairOver: PERCIVAL CR & BNRR
4.5 S JCT SR 8, Thurston, WA
Built 1995 Load: 53.5 t ADT: 37,225
CASE ROAD
FairOver: BEAVER CREEK
0.5 m S Maytown Rd, Thurston, WA
Built 1970 Load: 53.5 t ADT: 3,040
PENINSULA DRIVE
FairOver: ST.CLAIR LAKE
.1 m NW St Cl Dr, Thurston, WA
Built 1963 Load: 54.4 t ADT: 329
RICH ROAD
FairOver: SPURGEON CREEK
0.61 EAST OF OLD HWY 99, Thurston, WA
Built 2012 Load: 54.4 t ADT: 3,843
OLD HWY 99 SW
FairOver: SCATTER CREEK
3. NE JCT I5, Thurston, WA
Built 1923 Load: 55.3 t ADT: 7,789
TROSPER RD
FairOver: I-5
3.5 N JCT SR 121, Thurston, WA
Built 1991 Load: 58.0 t ADT: 21,420
I-5 S-E RAMP
FairOver: I-5 MAINLINE
2.4 N JCT SR 510, Thurston, WA
Built 1968 Load: 65.3 t ADT: 8,529
US 101
FairOver: PERRY CR
0.6 S JCT SR 8, Thurston, WA
Built 1957 Load: 66.2 t ADT: 25,346
SKOOKUMCHUCK ROAD
FairOver: SKOOKUMCHUCK RIVER
2.3 SE JCT SR507, Thurston, WA
Built 1984 Load: 66.2 t ADT: 981
W 4th Avenue
FairOver: Fill Slope
4th Avenue, Thurston, WA
Built 2004 Load: 67.7 t ADT: 20,060
OLD HWY 101
FairOver: SCHNEIDER CR
150 SE of Whittaker Rd, Thurston, WA
Built 1995 Load: 72.6 t ADT: 3,915
HAWKS PRAIRIE ROAD
FairOver: WOODLAND CREEK
150 ft S Johnson Point Rd, Thurston, WA
Built 1955 Load: 72.6 t ADT: 5,737
ISRAEL RD
FairOver: I-5
2.4 N JCT SR 121, Thurston, WA
Built 1990 Load: 73.5 t ADT: 6,934
RW JOHNSON RD
FairOver: BLACK LAKE DRAIN DITCH
0.11 S 21ST AVE, Thurston, WA
Built 2003 Load: 82.9 t ADT: 5,120
US 101
FairOver: BLACK LAKE BLVD
3.9 S JCT SR 8, Thurston, WA
Built 1995 Load: 89.8 t ADT: 45,840
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.