NH 45
Carrying NH 45 over SOUHEGAN RIVER
3.21 MI. N.OF MASON TL, Hillsborough, New Hampshire
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
NH 45 in Hillsborough, New Hampshire sits above 49% of rated New Hampshire bridges on inventory load rating (37 t), while its 1937 build year is earlier than 83% of Hillsborough's recorded-year cohort (385 bridges).
NH 45 in Hillsborough, New Hampshire is rated Fair in the FHWA's 2024 National Bridge Inventory. Built in 1937, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 5. The lowest applicable rating sets the federal condition category, so this Fair result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure NH:010400710010100
PRE-1950 · CONCRETE · SINGLE-SPAN · SUB-LED · ARTERIAL-ADT · STANDARD-LOAD · CAT-FAIR
- PRE-1950 Pre-1950
- CONCRETE Concrete
- SINGLE-SPAN Single span
- SUB-LED Substructure-led
- ARTERIAL-ADT Arterial ADT
- STANDARD-LOAD Standard load
- CAT-FAIR Fair
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: NH 45
The NH 45 bridge in Hillsborough, New Hampshire carries NH 45 over SOUHEGAN RIVER. It was built in 1937, making it 89 years old today. The structure is built primarily of concrete and spans 1 section, stretching 17.1 meters (56 feet) end to end. Daily traffic averages 2,660 vehicles, placing it in the moderately-trafficked tier of New Hampshire bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 6/9, substructure at 5/9. The weakest component sits in fair condition. None of this bridge's reported major components fall into the Poor condition range.
How NH 45 compares
Age against the county: built in 1937, earlier than 318 of Hillsborough's 385 bridges with a recorded construction year (83%), against a county median build year of 1973. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across New Hampshire bridges with a recorded inventory load rating (2,540 of 2,542 rated).
NH 45 vs every rated New Hampshire bridge
Inventory load rating (metric tons), FHWA NBI, this state
37 Top 51% higher than 49% of 2,540 bridges
rated New Hampshire bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
Hillsborough inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 385 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 1937
- Material
- Concrete
- Number of Spans
- 1
- Structure Length
- 17.1 m (56 ft)
- Deck Width
- 11.0 m (36 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 2,660 vehicles/day
- Structure Number
- 010400710010100
Condition Analysis
- • At 6/9, the deck (driving surface) shows fair condition, with minor wear flagged for upkeep.
- • The superstructure (beams and supports above the deck) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • At 5/9, the substructure (piers and abutments) shows fair condition, with minor wear flagged for upkeep.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether NH 45 is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare NH 45 against other structures in Hillsborough and across New Hampshire. New Hampshire bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for NH 45?
NH 45 in Hillsborough, New Hampshire has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 5/9 on the FHWA's 0–9 scale.
How often is NH 45 inspected?
NH 45's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 2,660 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. NH 45 is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for NH 45?
NH 45 has an NBI inventory load rating of 36.6 metric tons.
Who is responsible for maintaining NH 45?
NH 45 is owned and maintained by State Highway Agency.
How old is NH 45 and does age affect safety?
NH 45 was built in 1937, making it 89 years old.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Share this inspection record
Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.