US Bridges

County Seat HY/US9 over Tyndall Branch

Fair

Sussex County, Delaware · S/W of Georgetown · Structure no. 3659 028

Built
1920
105 years old, rebuilt 1995
Condition
Fair
inspected July 2023
Type
Arch - Deck
Concrete
Length
27 ft
1 main span
Daily traffic
6,883
2022 count
Owner
State
State Highway Agency

About this bridge

County Seat HY/US9 over Tyndall Branch is a concrete arch - deck carrying County Seat HY/US9 over Tyndall Branch in Sussex County, Delaware. It was built in 1920 and reconstructed in 1995, so it is 105 years old, older than the Delaware average of 47.3 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.

It carries about 6,883 vehicles a day, roughly 12% of them trucks, projected to reach 6,904 by 2042. The structure is 27 ft (8.2 m) long and 35 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesCounty Seat HY/US9
CrossesTyndall Branch
LocationS/W of Georgetown
RouteU.S. Route 9
CountySussex County
StateDelaware
Coordinates38.62359, -75.47859
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
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating107.1 US tons
Inventory rating96.5 US tons

Structure

Structure typeArch - Deck
MaterialConcrete
DeckNot applicable
Main spans1
Design loadUnknown
Structure length27 ft (8.2 m)
Longest span27 ft (8.2 m)
Deck width35 ft (10.7 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,883 (2022)
Projected traffic6,904 by 2042
Trucks12%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 County Seat HY/US9 over Tyndall Branch built?

It was built in 1920, making it 105 years old in 2025. It was reconstructed in 1995.

What condition is County Seat HY/US9 over Tyndall 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 July 2023.

How much traffic does County Seat HY/US9 over Tyndall Branch carry?

About 6,883 vehicles per day (2022 count), of which roughly 12% are trucks.

How long is County Seat HY/US9 over Tyndall Branch?

The structure is 27 ft (8.2 m) long with a longest span of 27 ft (8.2 m) and a deck 35 ft wide.

Who owns County Seat HY/US9 over Tyndall Branch?

It is owned by the State Highway Agency.