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I-25 Sbl over South Fork Castle Creek

Natrona County, Wyoming · rated Good in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

I-25 Sbl over South Fork Castle Creek in Natrona County, Wyoming, is rated in good condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
It was built in 1981, making it 44 years old at the 2025 inventory.
It carries about 1,520 vehicles a day (traffic count year 2024).
Its listed owner is the state highway agency.
It is one of 45 of the 135 inventoried bridges in Natrona County rated good (33.3%); 5 (3.7%) are rated poor.
A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.

Component ratings


Structure	Continuous steel stringer or multi-beam girder
Length	about 231 ft
Location	Casper - Kaycee
NBI structure number	DLZ
Condition class	Good

Source: FHWA National Bridge Inventory, 2025 data as reported by the Wyoming department of transportation.

Bridge	Built	Vehicles/day	Condition
Wyo 220 over Garden Creek	2001	26,351	Fair
Wyo 220 over North Platte River	1969	14,749	Fair
Wyo 220 over BNSF Railway	1969	14,641	Fair
I-25 Sbl over North McKinley Street	1958	12,618	Fair
I-25 Nbl over North McKinley Street	1958	12,577	Fair
I-25 NBL and SBL over Walsh Drive	2022	12,577	Good