Natrona County, WY

138 public highway bridges

Natrona County Bridge Snapshot

Natrona County, Wyoming contains 138 public highway bridges in the FHWA National Bridge Inventory. Roughly 22.5% are rated “Good,” 47.1% “Fair,” 3.6% “Poor,” and 3.6% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in WY are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

138
Total Bridges
22.5%
Good
3.6%
Poor
3.6%
Structurally Deficient

Condition Distribution

Good
22.5% (31)
Fair
47.1% (65)
Poor
3.6% (5)
SD
3.6% (5)

All Bridges (138)

WYO 256

Fair

Over: North Platte River

Jct Us 20 2687 - North, Natrona, WY

Built 1971 Load: 54.2 t ADT: 3,014

US 20

Fair

Over: North Platte River

Casper, Natrona, WY

Built 1979 Load: 76.2 t ADT: 12,085

I-25 Service Road

Good

Over: Sheep Creek

Bar Nunn North, Natrona, WY

Built 1950 Load: 12.4 t ADT: 85

I-25 Service Road

Good

Over: Unnamed Draw

Bar Nunn North, Natrona, WY

Built 1948 Load: 17.2 t ADT: 85

US 20/26/87 EBL

Good

Over: Elkhorn Creek

East Yellowstone - Casper, Natrona, WY

Built 1957 Load: 21.9 t ADT: 3,035

US 20/26/87 WBL

Good

Over: Elkhorn Creek

East Yellowstone - Casper, Natrona, WY

Built 1957 Load: 23.5 t ADT: 2,396

WYO 253

Good

Over: Dry Muddy Creek

Jct Us 20 2687 - South, Natrona, WY

Built 1955 Load: 28.1 t ADT: 460

US 20

Good

Over: Johnson Canal

Casper - Shoshoni, Natrona, WY

Built 1976 Load: 30.0 t ADT: 2,908

Na Cnty Rd 316

Good

Over: Casper Canal

20 Miles Sw Of Casper, Natrona, WY

Built 2003 Load: 30.8 t ADT: 5

W 25th Street

Good

Over: Garden Creek

Casper Streets, Natrona, WY

Built 1960 Load: 31.4 t ADT: 6,586

Na Cnty Rd 319

Good

Over: Casper Canal

Oregon Trail Road, Natrona, WY

Built 1998 Load: 31.8 t ADT: 6

I-25 NBL

Good

Over: Dry Muddy Creek

Douglas - Casper, Natrona, WY

Built 1966 Load: 32.7 t ADT: 4,193

I-25 SBL

Good

Over: Dry Muddy Creek

Douglas - Casper, Natrona, WY

Built 1966 Load: 32.7 t ADT: 4,702

WYO 487

Good

Over: Little Red Creek

Medicine Bow - Jt WYO 220, Natrona, WY

Built 1984 Load: 32.7 t ADT: 832

Na Cnty Rd 319

Good

Over: Casper Canal

14 Miles E. Of Casper, Natrona, WY

Built 1992 Load: 32.7 t ADT: 6

Na Cnty Rd 319

Good

Over: Casper Canal

15 Miles East Of Casper, Natrona, WY

Built 1998 Load: 32.7 t ADT: 6

E 2nd Street

Good

Over: Elkhorn Creek

Casper Streets, Natrona, WY

Built 2003 Load: 32.7 t ADT: 11,792

E 2nd Street

Good

Over: Claude Creek

East Casper, Natrona, WY

Built 2004 Load: 32.7 t ADT: 11,792

Na Cnty Rd 305

Good

Over: Unnamed Draw

Casper, Natrona, WY

Built 2015 Load: 32.7 t ADT: 5,027

I-25 NBL

Good

Over: Dugout Creek

Casper - Kaycee, Natrona, WY

Built 1979 Load: 33.6 t ADT: 1,499

I-25 SBL

Good

Over: Dugout Creek

Casper - Kaycee, Natrona, WY

Built 1979 Load: 33.6 t ADT: 1,439

Bryan Stock Trail

Good

Over: North Platte River

Casper, Natrona, WY

Built 1982 Load: 33.6 t ADT: 2,878

W 13th Street

Good

Over: Garden Creek

13Th St - Casper, Natrona, WY

Built 1992 Load: 33.6 t ADT: 6,940

US 20

Good

Over: Casper Canal

Casper - Shoshoni, Natrona, WY

Built 1976 Load: 34.3 t ADT: 2,908

I-25 NBL

Good

Over: Machinery Pass

Casper - Kaycee, Natrona, WY

Built 1972 Load: 34.5 t ADT: 2,677

I-25 SBL

Good

Over: Machinery Pass

Casper - Kaycee, Natrona, WY

Built 1972 Load: 34.5 t ADT: 2,648

US 20

Good

Over: South Fork Casper Creek

Casper - Shoshoni, Natrona, WY

Built 1976 Load: 36.3 t ADT: 2,908

Na Cnty Rd 402

Good

Over: Bates Creek

9 Mi SW of Rd Crk School, Natrona, WY

Built 2021 Load: 41.1 t ADT: 23

Na Cnty Rd 316

Good

Over: Casper Canal

15 Mi Sw Of Casper, Natrona, WY

Built 2004 Load: 45.4 t ADT: 5

Na Cnty Rd 106

Good

Over: BNSF Railway

Powder River Streets, Natrona, WY

Built 2022 Load: 45.4 t ADT: 20

Na Cnty Rd 131

Good

Over: Salt Creek

Midwest, Natrona, WY

Built 2012 Load: 46.8 t ADT: 596

I-25 NBL

Good

Over: South Fork Castle Creek

Casper - Kaycee, Natrona, WY

Built 1981 Load: 50.8 t ADT: 1,515

I-25 SBL

Good

Over: South Fork Castle Creek

Casper - Kaycee, Natrona, WY

Built 1981 Load: 50.8 t ADT: 1,464

Na Cnty Rd 412

Poor

Over: Hogback Draw

3 Miles Northeast Alcova, Natrona, WY

Built 1929 Load: 6.5 t ADT: 87

Na Cnty Rd 102

Poor

Over: Badwater Creek

20 Miles N.W. Of Arminto, Natrona, WY

Built 1940 Load: 11.8 t ADT: 22

Na Cnty Rd 110

Poor

Over: South Fork Powder River

44 Miles N.W. Of Casper, Natrona, WY

Built 1977 Load: 29.0 t ADT: 53

WYO 220

Poor

Over: Sweetwater River

Muddy Gap Jct-WYO 487 Jct, Natrona, WY

Built 1970 Load: 32.7 t ADT: 1,771

WYO 220

Poor

Over: Casper Canal

Muddy Gap Jct-WYO 487 Jct, Natrona, WY

Built 1967 Load: 39.0 t ADT: 3,066

Read our methodology — how this data is sourced, computed, and verified.

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Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial