NH111 WB over Merrimack River
Hillsborough County, New Hampshire · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- NH111 WB over Merrimack River in Hillsborough County, New Hampshire, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1970, making it 55 years old at the 2025 inventory.
- It carries about 17,275 vehicles a day (traffic count year 2023).
- Its listed owner is a city or municipal highway agency.
- It is one of 153 of the 385 inventoried bridges in Hillsborough County rated fair (39.7%); 31 (8.1%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 2023, on a 24-month routine inspection cycle.
- It is coded scour critical (NBI item 113 = 3): scour critical: foundations unstable for the assessed or calculated scour.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (42.76375, -71.44353)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 602 ft |
| Location | .1 Mi West of Jct Rt 3A |
| NBI structure number | 013101090006800 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 3: scour critical: foundations unstable for the assessed or calculated scour |
Source: FHWA National Bridge Inventory, 2025 data as reported by the New Hampshire department of transportation.
Busiest bridges in Hillsborough County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Fee Tpk N&S Ramps over Salmon Brook | 1955 | 128,889 | Good |
| Fee Tpk over Greeley Street | 1993 | 78,063 | Good |
| Fee Tpk over Souhegan River | 1953 | 75,081 | Good |
| Fee Tpk over Baboosic Brook | 1954 | 75,081 | Good |
| US 3 Fee Tpk NB over Nashua River | 1955 | 73,979 | Fair |
| US 3 Fee Tpk SB over Nashua River | 1959 | 71,221 | Good |
All bridges nearby: Hillsborough County, NH bridge conditions · every bridge in Hillsborough County · New Hampshire bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.