US 191
Carrying US 191 over YELLOWSTONE RIVER
1M N BIG TIMBER, Sweet Grass, Montana
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
US 191 in Sweet Grass, Montana sits above 35% of rated Montana bridges on inventory load rating (26 t), while its 1938 build year is earlier than 87% of Sweet Grass's recorded-year cohort (94 bridges).
US 191 in Sweet Grass, Montana is rated Fair in the FHWA's 2024 National Bridge Inventory. Built in 1938, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 6. 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 MT:P00045000+09831
PRE-1950 · STEEL · MULTI-SPAN · TIED-CTRL · ARTERIAL-ADT · STANDARD-LOAD · CAT-FAIR
- PRE-1950 Pre-1950
- STEEL Steel
- MULTI-SPAN 3 spans
- TIED-CTRL Tied control
- 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: US 191
The US 191 bridge in Sweet Grass, Montana carries US 191 over YELLOWSTONE RIVER. It was built in 1938, making it 88 years old today. The structure is built primarily of steel continuous and spans 3 sections, stretching 115.8 meters (380 feet) end to end. Daily traffic averages 1,689 vehicles, placing it in the moderately-trafficked tier of Montana 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 6/9. The weakest component sits in fair condition. No reported major component scores in the Poor range under the current federal condition thresholds.
How US 191 compares
Age against the county: built in 1938, earlier than 82 of Sweet Grass's 94 bridges with a recorded construction year (87%), against a county median build year of 1980. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Montana bridges with a recorded inventory load rating (5,144 of 5,224 rated).
US 191 vs every rated Montana bridge
Inventory load rating (metric tons), FHWA NBI, this state
26 Top 65% higher than 35% of 5,144 bridges
rated Montana 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.
Sweet Grass inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 94 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
- 1938
- Material
- Steel Continuous
- Number of Spans
- 3
- Structure Length
- 115.8 m (380 ft)
- Deck Width
- 8.4 m (28 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 1,689 vehicles/day
- Structure Number
- P00045000+09831
Condition Analysis
- • The deck (driving surface) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
- • At 6/9, the superstructure (beams and supports above the deck) shows fair condition, with minor wear flagged for upkeep.
- • At 6/9, 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 US 191 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 US 191 against other structures in Sweet Grass and across Montana. Montana 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 US 191?
US 191 in Sweet Grass, Montana has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is US 191 inspected?
US 191'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 1,689 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 191 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 US 191?
US 191 has an NBI inventory load rating of 26.3 metric tons.
Who is responsible for maintaining US 191?
US 191 is owned and maintained by State Highway Agency.
How old is US 191 and does age affect safety?
US 191 was built in 1938, making it 88 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.