County profile · official public datasets

Grant County, WI

383 public highway bridges tracked in the FHWA National Bridge Inventory: 66.1% rated Good, 29.5% Fair, 4.4% Poor.

383
Public bridges: 66.1%
Good condition: 4.4%
Poor condition

The verdict

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

Grant County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 32%
lowest Poor share in state: 4.4%
Poor-condition share: 383
public highway bridges: 1984
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.

Grant County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Grant County ranks #23 of 72 Wisconsin counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.4%). Grant County, Wisconsin contains 383 public highway bridges. Roughly 66.1% are rated “Good,” 29.5% “Fair,” and 4.4% “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

383

Public highway bridges in Grant County

Good condition

66.1%

253 of 383 rated 7-9

Fair condition

29.5%

113 of 383 rated 5-6

Poor condition

4.4%

17 of 383 rated 4 or below

In-state Poor-share rank

#23 of 72

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

Condition distribution

Share of 383 NBI-tracked bridges by lowest applicable component rating.

Good

66.1% (253)

Fair

29.5% (113)

Poor

4.4% (17)

Grant County's Poor-condition bridges carry 5,024 vehicle crossings a day

That is 1.4% of the county's reported daily bridge traffic on 4.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 296 crossings a day against 871 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 383 of 383 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

28.5% of Grant County's bridges have passed the 50-year mark

109 of the 383 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 66.1% 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 23.9% of the county's Poor-condition bridge traffic

CTH T over WISCONSIN RIVER 03, built 1958, carries 1,200 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 17-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 5,024 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

1
1900s

1
1910s

2
1920s

4
1930s

14
1940s

5
1950s

27
1960s

32
1970s

52
1980s

61
1990s

75
2000s

74
2010s

27
2020s

8

What this shows Construction peaked in the 1990s, when 75 of the county's bridges still in the inventory were built, which is 19.6% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1984) matches the Wisconsin average (1984).

How Grant County compares with Wisconsin's closest counties by inventory size

The 5 Wisconsin counties nearest Grant County in number of bridges, with their condition splits. Its 4.4% Poor share is the 2nd-lowest of these 6. Its average build year of 1984 against a peer-group mean of 1982 is in line with the group.

Showing the 5 closest of 71 Wisconsin counties eligible for comparison.

Bridge inventory size and condition shares for Grant County and the 5 Wisconsin counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Grant County (this page)	383	66.1%	29.5%	4.4%	1984
Monroe County	374	50.5%	46%	3.5%	1981
Waukesha County	369	53.1%	40.4%	6.5%	1984
Chippewa County	359	34.8%	56%	9.2%	1985
Vernon County	333	44.1%	48.3%	7.5%	1983
Barron County	319	48.6%	45.8%	5.6%	1978

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 Grant 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 Grant County, both outside Wisconsin so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside WI (383 bridges here).

Trumbull County, OH · 383 bridges
Webb County, TX · 383 bridges
Bristol County, MA · 384 bridges
Custer County, OK · 384 bridges

Similar average build year

Nearest mean year-built outside WI (1984 here).

Hennepin County, MN · avg 1984 · 936 bridges
Duval County, FL · avg 1984 · 831 bridges
El Paso County, CO · avg 1984 · 686 bridges
Bell County, TX · avg 1984 · 660 bridges

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

All 383 Good 253 Fair 113 Poor 17

Good-condition bridges (253)

Sort:

Grant County Bridge Snapshot

Condition distribution

Grant County's Poor-condition bridges carry 5,024 vehicle crossings a day

28.5% of Grant County's bridges have passed the 50-year mark

One structure carries 23.9% of the county's Poor-condition bridge traffic

How Grant County compares with Wisconsin's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Good-condition bridges (253)

LRD PARK RD (DEAD

LRD ROCK RD

LRD OLD LANCASTER

LRD HICKLIN HOLLOW

CTH C

LRD WILSON HILL RD

LRD GRANEY RD

CTH VV

LRD TORMEY RD

LRD BIG GREEN RD

LRD ALDERSON RD

LRD SOUTH RIDGE RD

LRD PLEASANT VALLE

LRD MARIAN RD

LRD MILNER RD

LRD UNIVERSITY FAR

LRD BORAH RD

LRD HYPOINT RD

LRD FAIRVIEW RD

LRD OLD POTOSI RD

LRD SINSINAWA RD

LRD MILL RD

LRD SOUTHWEST RD

LRD BLUE SCHOOL RD

LRD ALDERSON RD

LRD GREEN RIVER RD

LRD CUSHMAN RD

LRD SHADY DELL RD

LRD GRANDVIEW RD

LRD GREEN RIVER RD

LRD INDIAN CREEK R

LRD ELLENBORO RD

LRD ROCK SCHOOL RD

LRD PIGEON RIVER R

LRD BORAH RD

LRD SPRUCE ROAD

LRD OLD HWY C RD

LRD BAUMGARTNER RD

LRD CROSSCUT RD

LRD GRAYS MILL RD

STH 35-STH 133

LRD KANSAS ST

CTH A

CTH U

STH 133

LRD MILLVILLE HOLL

LRD REYNOLDS RIDGE

CTH C

LRD DIAMOND GROVE

CTH X

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