US Bridges

US-421 over Rock House Branch

FairPosted for load

Leslie County, Kentucky · 3.4 MI West of JCT Ky 118 · Structure no. 066B00015N

Built
1932
93 years old
Condition
Fair
inspected December 2023
Type
Culvert
Concrete
Length
21 ft
2 main spans
Daily traffic
1,059
2022 count
Owner
State
State Highway Agency

About this bridge

US-421 over Rock House Branch is a concrete culvert carrying US-421 over Rock House Branch in Leslie County, Kentucky. It was built in 1932, so it is 93 years old, older 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 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. Its operating status is: posted for load restriction.

It carries about 1,059 vehicles a day, roughly 5% of them trucks, projected to reach 1,059 by 2042. The structure is 21 ft (6.4 m) long. If it were closed, the detour would be 37.9 mi (61 km).

Location

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CarriesUS-421
CrossesRock House Branch
Location3.4 MI West of JCT Ky 118
RouteU.S. Route 421
CountyLeslie County
StateKentucky
Coordinates37.14083, -83.43611
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
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating43 US tons
Inventory rating20 US tons

Structure

Structure typeCulvert
MaterialConcrete
DeckNot applicable
Main spans2
Design loadH 15
Structure length21 ft (6.4 m)
Longest span10 ft (3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,059 (2022)
Projected traffic1,059 by 2042
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed37.9 mi (61 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US-421 over Rock House Branch built?

It was built in 1932, making it 93 years old in 2025.

What condition is US-421 over Rock House Branch 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 December 2023.

How much traffic does US-421 over Rock House Branch carry?

About 1,059 vehicles per day (2022 count), of which roughly 5% are trucks.

How long is US-421 over Rock House Branch?

The structure is 21 ft (6.4 m) long with a longest span of 10 ft (3 m).

Who owns US-421 over Rock House Branch?

It is owned by the State Highway Agency.