US 101 over Hamma Hamma River
Mason County, Washington · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 101 over Hamma Hamma River in Mason County, Washington, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 1924, making it 101 years old at the 2025 inventory.
- It carries about 2,911 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 77 of the 136 inventoried bridges in Mason County rated good (56.6%); 4 (2.9%) are rated poor.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (47.54578, -123.04261)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 7 | Good condition |
| Substructure | 7 | Good condition |
Bridge details
| Structure | Concrete through arch |
| Length | about 153 ft |
| Location | 5.3 S Jefferson Co |
| NBI structure number | 0000734B0000000 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Washington department of transportation.
Busiest bridges in Mason County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 101 over Mill Creek | 1973 | 19,397 | Good |
| US 101 over Creek/rr/street | 1973 | 18,182 | Fair |
| US 101 over Matlock Rd | 1973 | 18,182 | Poor |
| SR 3 over Goldsborough Creek | 1923 | 17,285 | Fair |
| US 101 over SR 3 | 1972 | 17,050 | Fair |
| SR 3 over Deer Creek | 1957 | 15,878 | Good |
All bridges nearby: Mason County, WA bridge conditions · every bridge in Mason County · Washington bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.