County profile · official public datasets

Brown County, WI

466 public highway bridges tracked in the FHWA National Bridge Inventory: 51.3% rated Good, 44.8% Fair, 3.9% Poor.

466
Public bridges: 51.3%
Good condition: 3.9%
Poor condition

The verdict

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

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

Top 25%
lowest Poor share in state: 3.9%
Poor-condition share: 466
public highway bridges: 1990
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.

Brown County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Brown County ranks #18 of 72 Wisconsin counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 3.9%). Brown County, Wisconsin contains 466 public highway bridges. Roughly 51.3% are rated “Good,” 44.8% “Fair,” and 3.9% “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

466

Public highway bridges in Brown County

Good condition

51.3%

239 of 466 rated 7-9

Fair condition

44.8%

209 of 466 rated 5-6

Poor condition

3.9%

18 of 466 rated 4 or below

In-state Poor-share rank

#18 of 72

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

Condition distribution

Share of 466 NBI-tracked bridges by lowest applicable component rating.

Good

51.3% (239)

Fair

44.8% (209)

Poor

3.9% (18)

Brown County's Poor-condition bridges carry 62,050 vehicle crossings a day

That is 0.9% of the county's reported daily bridge traffic on 3.9% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 3,447 crossings a day against 13,869 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 466 of 466 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

22.1% of Brown County's bridges have passed the 50-year mark

103 of the 466 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 51.3% 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 18.3% of the county's Poor-condition bridge traffic

LRD LARSON RD over BEAVER CREEK, built 1978, carries 11,375 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 18-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 62,050 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

2
1920s

5
1930s

1
1940s

4
1950s

16
1960s

17
1970s

107
1980s

95
1990s

45
2000s

39
2010s

119
2020s

16

What this shows Construction peaked in the 2010s, when 119 of the county's bridges still in the inventory were built, which is 25.5% of those with a recorded year. That cohort is now 5 to 14 years old in the 2024 inventory. Its average build year is 1990, 6 years newer than the Wisconsin average of 1984.

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

The 5 Wisconsin counties nearest Brown County in number of bridges, with their condition splits. Its 3.9% Poor share is the 2nd-lowest of these 6. Its average build year of 1990 against a peer-group mean of 1983 is 7 years newer.

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

Bridge inventory size and condition shares for Brown County and the 5 Wisconsin counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Marathon County	530	46.4%	43.4%	10.2%	1982
Brown County (this page)	466	51.3%	44.8%	3.9%	1990
Grant County	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

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

Similar inventory size

Nearest county inventories outside WI (466 bridges here).

Sangamon County, IL · 466 bridges
Winnebago County, IL · 467 bridges
Broome County, NY · 468 bridges
Jefferson County, CO · 464 bridges

Similar average build year

Nearest mean year-built outside WI (1990 here).

Maricopa County, AZ · avg 1990 · 2,847 bridges
Tarrant County, TX · avg 1990 · 2,617 bridges
Fairfax County, VA · avg 1990 · 751 bridges
Guilford County, NC · avg 1990 · 736 bridges

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

All 466 Good 239 Fair 209 Poor 18

Good-condition bridges (239)

Sort:

Brown County Bridge Snapshot

Condition distribution

Brown County's Poor-condition bridges carry 62,050 vehicle crossings a day

22.1% of Brown County's bridges have passed the 50-year mark

One structure carries 18.3% of the county's Poor-condition bridge traffic

How Brown 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 (239)

STH OLD STH 29/ ST

LRD PINE GROVE ROA

LRD CREAMERY ROAD

LRD MANITOWOC ROAD

LRD SANTA MONICA D

LRD PINE GROVE ROA

LRD BRAYDEN LANE

LRD BRAYDEN LANE

LRD SANCTUARY ROAD

LRD MEMORIAL DR

IH 41

IH 41 SB

IH 41 NB

STH 54

IH 41 SB

IH 41-STH 32

IH 29 EB TO IH 41

IH 41 SB TO 29 WB

IH 41

IH 41

USH 141-STH 29

LRD LITTLE RAPIDS

IH 41 NB

IH 41 NB

IH 41 SB

IH 41 NB

IH 41 NB

IH 41 SB

IH 41 NB

STH 96

LRD HANSEN ROAD

IH 41 NB ON-RAMP F

IH STH 29 EB TO IH

IH 41 SB

IH 41 SB

IH I41 NB OFF RAMP

STH 172 WB

LRD DALY DRIVE

IH 43 NB

STH 29 - WALNUT ST

STH 29 - WALNUT ST

CTH EB

CTH EB

LRD CENTENNIAL CEN

IH I41 SB OFF RAMP

IH 41 NB TO STH 32

IH 43 NB OFF RAMP

CTH GE NB

CTH EE

CTH V

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