County profile · official public datasets

Johnson County, WY

204 public highway bridges tracked in the FHWA National Bridge Inventory: 26.5% rated Good, 70.6% Fair, 2.9% Poor.

204
Public bridges: 26.5%
Good condition: 2.9%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

Johnson County pairs a top-quartile lowest Poor-condition share among rated counties in the state with an older average build year than the state inventory.

Top 17%
lowest Poor share in state: 2.9%
Poor-condition share: 204
public highway bridges: 1970
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

Johnson County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Johnson County ranks #4 of 23 Wyoming counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.9%). Johnson County, Wyoming contains 204 public highway bridges. Roughly 26.5% are rated “Good,” 70.6% “Fair,” and 2.9% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

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

Total bridges

204

Public highway bridges in Johnson County

Good condition

26.5%

54 of 204 rated 7-9

Fair condition

70.6%

144 of 204 rated 5-6

Poor condition

2.9%

6 of 204 rated 4 or below

In-state Poor-share rank

#4 of 23

Among Wyoming counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 204 NBI-tracked bridges by lowest applicable component rating.

Good

26.5% (54)

Fair

70.6% (144)

Poor

2.9% (6)

Johnson County's Poor-condition bridges carry 1,800 vehicle crossings a day

That is 0.6% of the county's reported daily bridge traffic on 2.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 300 crossings a day against 1,157 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 204 of 204 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

75.5% of Johnson County's bridges have passed the 50-year mark

154 of the 204 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 26.5% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 79.9% of the county's Poor-condition bridge traffic

I-25 SBL over South Fork Powder River, built 1960, carries 1,439 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 6-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 1,800 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1930s

3
1940s

3
1950s

16
1960s

115
1970s

26
1980s

14
1990s

8
2000s

13
2010s

6

What this shows Construction peaked in the 1960s, when 115 of the county's bridges still in the inventory were built, which is 56.4% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year is 1970, 6 years older than the Wyoming average of 1976.

How Johnson County compares with Wyoming's closest counties by inventory size

The 5 Wyoming counties nearest Johnson County in number of bridges, with their condition splits. Its 2.9% Poor share is the 2nd-lowest of these 6. Its average build year of 1970 against a peer-group mean of 1977 is 7 years older.

Showing the 5 closest of 22 Wyoming counties eligible for comparison.

Bridge inventory size and condition shares for Johnson County and the 5 Wyoming counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Carbon County	206	38.8%	54.4%	6.8%	1973
Johnson County (this page)	204	26.5%	70.6%	2.9%	1970
Sweetwater County	191	28.8%	62.8%	8.4%	1976
Park County	187	37.4%	58.3%	4.3%	1979
Fremont County	177	47.5%	46.3%	6.2%	1981
Crook County	176	30.7%	67.6%	1.7%	1974

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to Johnson County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for Johnson County, both outside Wyoming so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside WY (204 bridges here).

Greene County, AL · 204 bridges
Flathead County, MT · 204 bridges
Pembina County, ND · 204 bridges
Okfuskee County, OK · 204 bridges

Similar average build year

Nearest mean year-built outside WY (1970 here).

Hamilton County, OH · avg 1970 · 783 bridges
Yavapai County, AZ · avg 1970 · 543 bridges
Garfield County, OK · avg 1970 · 504 bridges
San Luis Obispo County, CA · avg 1970 · 401 bridges

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 204 Good 54 Fair 144 Poor 6

All bridges (204)

Sort:

Johnson County Bridge Snapshot

Condition distribution

Johnson County's Poor-condition bridges carry 1,800 vehicle crossings a day

75.5% of Johnson County's bridges have passed the 50-year mark

One structure carries 79.9% of the county's Poor-condition bridge traffic

How Johnson County compares with Wyoming's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (204)

I-25 SBL

I-90 EBL

I-90 WBL

I-90 EBL

I-90 WBL

I-25 NBL

I-25 SBL

I-90 WBL

I-90 EBL

I-90 WBL

I-90 EBL

I-90 WBL

I-90 EBL

I-90 WBL

I-90 EBL

I-90 WBL

I-90 EBL

I-90 WBL

I-25 SBL

I-25 NBL

I-25 SBL

I-25 NBL

I-25 SBL

I-25 NBL

I-90 EBL

I-90 WBL

I-90 EBL

FDR 28

I-90 EBL

I-90 WBL

I-25 NBL

I-25 SBL

I-25 SBL

I-25 SBL

I-90 EBL

I-90 EBL

I-90 WBL

I-90 EBL

I-90 WBL

WYO 387

Jo Cnty Rd 132

Jo Cnty Rd 252

Lowr Powder Rvr Rd

WYO 192

I-25 NBL

I-25 SBL

I-25 NBL

I-90 EBL

I-25 SBL

I-25 NBL

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