US Bridges

S 21 over Elk Creek 119

Fair

Lewis and Clark County, Montana · 1M NE Augusta · Structure no. L25400000+02001

Built
1935
90 years old
Condition
Fair
inspected March 2024
Type
Tee Beam
Concrete
Length
80 ft
2 main spans
Daily traffic
260
2023 count
Owner
State
State Highway Agency

About this bridge

S 21 over Elk Creek 119 is a concrete tee beam carrying S 21 over Elk Creek 119 in Lewis and Clark County, Montana. It was built in 1935, so it is 90 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 260 vehicles a day, roughly 5% of them trucks, projected to reach 273 by 2043. The structure is 80 ft (24.4 m) long and 25 ft wide. If it were closed, the detour would be 11.2 mi (18 km).

Location

Open in Google Maps
CarriesS 21
CrossesElk Creek 119
Location1M NE Augusta
RouteState Highway 21
CountyLewis and Clark County
StateMontana
Coordinates47.50238, -112.36717
Functional classRural Major Collector

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating42 US tons
Inventory rating32 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans2
Design loadH 15
Structure length80 ft (24.4 m)
Longest span39 ft (12 m)
Deck width25 ft (7.6 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic260 (2023)
Projected traffic273 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.2 mi (18 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was S 21 over Elk Creek 119 built?

It was built in 1935, making it 90 years old in 2025.

What condition is S 21 over Elk Creek 119 in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in March 2024.

How much traffic does S 21 over Elk Creek 119 carry?

About 260 vehicles per day (2023 count), of which roughly 5% are trucks.

How long is S 21 over Elk Creek 119?

The structure is 80 ft (24.4 m) long with a longest span of 39 ft (12 m) and a deck 25 ft wide.

Who owns S 21 over Elk Creek 119?

It is owned by the State Highway Agency.