US Bridges

Md 313 over Unicorn Branch

Fair

Queen Anne's County, Maryland · 0.92 Mile North of Md 544 · Structure no. 100000170031010

Built
1924
101 years old, rebuilt 1950
Condition
Fair
inspected April 2024
Type
Slab
Concrete
Length
43 ft
3 main spans
Daily traffic
1,970
2009 count
Owner
State
State Highway Agency

About this bridge

Md 313 over Unicorn Branch is a concrete slab carrying Md 313 over Unicorn Branch in Queen Anne's County, Maryland. It was built in 1924 and reconstructed in 1950, so it is 101 years old, older than the Maryland average of 52.6 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 1,970 vehicles a day, roughly 8% of them trucks, projected to reach 3,369 by 2026. The structure is 43 ft (13.1 m) long and 43 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesMd 313
CrossesUnicorn Branch
Location0.92 Mile North of Md 544
RouteState Highway 313
CountyQueen Anne's County
StateMaryland
Coordinates39.24993, -75.8615
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating61.9 US tons
Inventory rating37 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckOther
Main spans3
Design loadH 20
Structure length43 ft (13.1 m)
Longest span17 ft (5.2 m)
Deck width43 ft (13 m)
Roadway width41 ft (12.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,970 (2009)
Projected traffic3,369 by 2026
Trucks8%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 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 Md 313 over Unicorn Branch built?

It was built in 1924, making it 101 years old in 2025. It was reconstructed in 1950.

What condition is Md 313 over Unicorn 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 April 2024.

How much traffic does Md 313 over Unicorn Branch carry?

About 1,970 vehicles per day (2009 count), of which roughly 8% are trucks.

How long is Md 313 over Unicorn Branch?

The structure is 43 ft (13.1 m) long with a longest span of 17 ft (5.2 m) and a deck 43 ft wide.

Who owns Md 313 over Unicorn Branch?

It is owned by the State Highway Agency.