County profile · official public datasets

Portage County, WI

182 public highway bridges tracked in the FHWA National Bridge Inventory: 53.3% rated Good, 44% Fair, 2.7% Poor.

182
Public bridges: 53.3%
Good condition: 2.7%
Poor condition

The verdict

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

Portage County pairs a top-10% lowest Poor-condition share among rated counties in the state with a newer average build year than the state inventory.

Top 6%
lowest Poor share in state: 2.7%
Poor-condition share: 182
public highway bridges: 1991
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.

Portage County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Portage County ranks #4 of 72 Wisconsin counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.7%). Portage County, Wisconsin contains 182 public highway bridges. Roughly 53.3% are rated “Good,” 44% “Fair,” and 2.7% “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

182

Public highway bridges in Portage County

Good condition

53.3%

97 of 182 rated 7-9

Fair condition

44%

80 of 182 rated 5-6

Poor condition

2.7%

5 of 182 rated 4 or below

In-state Poor-share rank

#4 of 72

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

Condition distribution

Share of 182 NBI-tracked bridges by lowest applicable component rating.

Good

53.3% (97)

Fair

44% (80)

Poor

2.7% (5)

Portage County's Poor-condition bridges carry 4,105 vehicle crossings a day

That is 0.5% of the county's reported daily bridge traffic on 2.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 821 crossings a day against 4,753 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 182 of 182 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

27.5% of Portage County's bridges have passed the 50-year mark

50 of the 182 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 53.3% 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 30.5% of the county's Poor-condition bridge traffic

CTH O over MILL CREEK, built 1975, carries 1,250 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 5-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 4,105 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

3
1930s

2
1940s

4
1950s

2
1960s

28
1970s

21
1980s

18
1990s

14
2000s

60
2010s

24
2020s

6

What this shows Construction peaked in the 2000s, when 60 of the county's bridges still in the inventory were built, which is 33% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year is 1991, 7 years newer than the Wisconsin average of 1984.

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

The 5 Wisconsin counties nearest Portage County in number of bridges, with their condition splits. Its 2.7% Poor share is the 1st-lowest of these 6. Its average build year of 1991 against a peer-group mean of 1983 is 8 years newer.

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

Bridge inventory size and condition shares for Portage County and the 5 Wisconsin counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Columbia County	183	30.1%	63.9%	6%	1977
Jefferson County	182	57.1%	37.4%	5.5%	1987
Portage County (this page)	182	53.3%	44%	2.7%	1991
Taylor County	176	58.5%	30.1%	11.4%	1988
Juneau County	172	49.4%	47.7%	2.9%	1981
Waupaca County	169	76.3%	20.7%	3%	1984

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

Similar inventory size

Nearest county inventories outside WI (182 bridges here).

Logan County, CO · 182 bridges
Ida County, IA · 182 bridges
Wright County, IA · 182 bridges
Pulaski County, KY · 182 bridges

Similar average build year

Nearest mean year-built outside WI (1991 here).

Denver County, CO · avg 1991 · 458 bridges
Baldwin County, AL · avg 1991 · 381 bridges
Union County, NC · avg 1991 · 353 bridges
Rock County, MN · avg 1991 · 265 bridges

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

All 182 Good 97 Fair 80 Poor 5

All bridges (182)

Sort:

Portage County Bridge Snapshot

Condition distribution

Portage County's Poor-condition bridges carry 4,105 vehicle crossings a day

27.5% of Portage County's bridges have passed the 50-year mark

One structure carries 30.5% of the county's Poor-condition bridge traffic

How Portage 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

All bridges (182)

LRD FIRST STREET

STH 66

USH10 EB

USH 10 WB

LRD MILL ST

CTH S

STH66EB

LRD 110TH ST

LRD SUNSET DR

STH 34

USH 10 EB

USH 10 EB RAMP

USH 10 WB RAMP

USH 10 EB

USH 10 WB

CTH Q

IH 39 NB/USH 51 NB

CTH Y

LRD 100TH ST

LRD W RIVER DRIVE

LRD PORTER ROAD

LRD TOWER ROAD

LRD SHARON WOOD RD

STH 13/34

LRD BENTLEY RD

LRD COUNTY ROAD R

USH10 EB

USH 10 WB

CTH Q

STH 66

CTH X

LRD LINDEN RD

LRD CTH R

IH USH 51-IH 39

USH B51-POST RD

LRD BRIDGE ROAD

CTH J NB

CTH J SB

USH 10 WB

LRD KEENER RD

CTH Y

STH 13/34 S OVER U

CTH G

LRD STONEY HILL RO

CTH U

CTH HH

USH 10 EB

USH 10 WB

USH 10 EB

STH 66

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