US Bridges

US 421 over Little Kentucky River

Fair

Trimble County, Kentucky · 0.15 MI N of Ky 316 · Structure no. 112B00023N

Built
1982
43 years old
Condition
Fair
inspected October 2023
Type
Box Beam or Girders - Single or Spread
Prestressed Concrete Continuous
Length
228 ft
6 main spans
Daily traffic
2,170
2021 count
Owner
State
State Highway Agency

About this bridge

US 421 over Little Kentucky River is a prestressed concrete continuous box beam or girders - single or spread carrying US 421 over Little Kentucky River in Trimble County, Kentucky. It was built in 1982, so it is 43 years old, younger than the Kentucky average of 46.6 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 2,170 vehicles a day, roughly 13% of them trucks, projected to reach 2,170 by 2041. The structure is 228 ft (69.5 m) long and 37 ft wide. If it were closed, the detour would be 6.2 mi (10 km).

Location

Open in Google Maps
CarriesUS 421
CrossesLittle Kentucky River
Location0.15 MI N of Ky 316
RouteU.S. Route 421
CountyTrimble County
StateKentucky
Coordinates38.56028, -85.27583
Functional classRural Minor Arterial

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.
Superstructure8 Very GoodNo problems noted.
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 inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating95.7 US tons
Inventory rating57.4 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHS 20
Structure length228 ft (69.5 m)
Longest span35 ft (10.6 m)
Deck width37 ft (11.4 m)
Roadway width34 ft (10.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,170 (2021)
Projected traffic2,170 by 2041
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.2 mi (10 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 US 421 over Little Kentucky River built?

It was built in 1982, making it 43 years old in 2025.

What condition is US 421 over Little Kentucky River 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 October 2023.

How much traffic does US 421 over Little Kentucky River carry?

About 2,170 vehicles per day (2021 count), of which roughly 13% are trucks.

How long is US 421 over Little Kentucky River?

The structure is 228 ft (69.5 m) long with a longest span of 35 ft (10.6 m) and a deck 37 ft wide.

Who owns US 421 over Little Kentucky River?

It is owned by the State Highway Agency.