US 4 over Merrimack River
GoodMerrimack County, New Hampshire · Canterbury T.L. · Structure no. 002601420003800
- Built
- 2005
- 20 years old
- Condition
- Good
- inspected July 2023
- Type
- Stringer/Multi-beam or Girder
- Steel Continuous
- Length
- 593 ft
- 4 main spans
- Daily traffic
- 15,071
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 4 over Merrimack River is a steel continuous stringer/multi-beam or girder carrying US 4 over Merrimack River in Merrimack County, New Hampshire. It was built in 2005, so it is 20 years old, younger than the New Hampshire average of 56.9 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 15,071 vehicles a day, roughly 5% of them trucks, projected to reach 22,305 by 2043. The structure is 593 ft (180.7 m) long and 56 ft wide. If it were closed, the detour would be 6.8 mi (11 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 8 Very Good | No problems noted. |
| Superstructure | 8 Very Good | No problems noted. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US 4 over Merrimack River built?
It was built in 2005, making it 20 years old in 2025.
What condition is US 4 over Merrimack River in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in July 2023.
How much traffic does US 4 over Merrimack River carry?
About 15,071 vehicles per day (2023 count), of which roughly 5% are trucks.
How long is US 4 over Merrimack River?
The structure is 593 ft (180.7 m) long with a longest span of 130 ft (39.6 m) and a deck 56 ft wide.
Who owns US 4 over Merrimack River?
It is owned by the State Highway Agency.