County profile · official public datasets

Polk County, MN

268 public highway bridges tracked in the FHWA National Bridge Inventory: 63.1% rated Good, 33.6% Fair, 3.4% Poor.

268
Public bridges: 63.1%
Good condition: 3.4%
Poor condition

The verdict

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

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

Top 46%
lowest Poor share in state: 3.4%
Poor-condition share: 268
public highway bridges: 1989
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.

Polk County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Polk County ranks #40 of 87 Minnesota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 3.4%). Polk County, Minnesota contains 268 public highway bridges. Roughly 63.1% are rated “Good,” 33.6% “Fair,” and 3.4% “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

268

Public highway bridges in Polk County

Good condition

63.1%

169 of 268 rated 7-9

Fair condition

33.6%

90 of 268 rated 5-6

Poor condition

3.4%

9 of 268 rated 4 or below

In-state Poor-share rank

#40 of 87

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

Condition distribution

Share of 268 NBI-tracked bridges by lowest applicable component rating.

Good

63.1% (169)

Fair

33.6% (90)

Poor

3.4% (9)

Polk County's Poor-condition bridges carry 19,333 vehicle crossings a day

That is 13.6% of the county's reported daily bridge traffic on 3.4% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 2,148 crossings a day against 253 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 268 of 268 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

17.9% of Polk County's bridges have passed the 50-year mark

48 of the 268 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 63.1% 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 80% of the county's Poor-condition bridge traffic

US 2 over RED RIVER, built 1963, carries 15,475 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 9-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 19,333 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

7
1930s

3
1940s

2
1950s

6
1960s

18
1970s

34
1980s

38
1990s

60
2000s

76
2010s

17
2020s

7

What this shows Construction peaked in the 2000s, when 76 of the county's bridges still in the inventory were built, which is 28.4% of those with a recorded year. That cohort is now 15 to 24 years old in the 2024 inventory. Its average build year (1989) matches the Minnesota average (1986).

How Polk County compares with Minnesota's closest counties by inventory size

The 5 Minnesota counties nearest Polk County in number of bridges, with their condition splits. Its 3.4% Poor share is the 5th-lowest of these 6. Its average build year of 1989 against a peer-group mean of 1985 is in line with the group.

Showing the 5 closest of 86 Minnesota counties eligible for comparison.

Bridge inventory size and condition shares for Polk County and the 5 Minnesota counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Nobles County	304	70.7%	27.6%	1.6%	1983
Polk County (this page)	268	63.1%	33.6%	3.4%	1989
Rock County	265	80%	17.7%	2.3%	1991
Dakota County	259	44%	54.4%	1.5%	1986
Winona County	237	43%	52.3%	4.6%	1982
Lyon County	234	75.2%	21.8%	3%	1983

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

Similar inventory size

Nearest county inventories outside MN (268 bridges here).

Jackson County, MS · 268 bridges
Warren County, NJ · 268 bridges
Niagara County, NY · 268 bridges
Delaware County, OH · 268 bridges

Similar average build year

Nearest mean year-built outside MN (1989 here).

Harris County, TX · avg 1989 · 4,029 bridges
Mecklenburg County, NC · avg 1989 · 746 bridges
Buffalo County, NE · avg 1989 · 459 bridges
Brazos County, TX · avg 1989 · 370 bridges

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

All 268 Good 169 Fair 90 Poor 9

Fair-condition bridges (90)

Sort:

Polk County Bridge Snapshot

Condition distribution

Polk County's Poor-condition bridges carry 19,333 vehicle crossings a day

17.9% of Polk County's bridges have passed the 50-year mark

One structure carries 80% of the county's Poor-condition bridge traffic

How Polk County compares with Minnesota's closest counties by inventory size

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

Fair-condition bridges (90)

CSAH 15

CSAH 65

US 2B

CSAH 64

CSAH 51

T 94

MSAS 113

MN 220

T 97

UNDETERMINED RD

US 59

US 2

US 75

MN 9

MN 102

US 75

US 75

MN 220

CSAH 62

MSAS 144

CR 217

MN 9

CSAH 6

CSAH 66

CR 228

CSAH 11

T 407

CSAH 20

CSAH 19

MN 220

CSAH 20

CR 232

US 59

CSAH 67

CSAH 45

MN 220

T 105

US 75

CSAH 28

CSAH 22

CR 226

CSAH 14

CSAH 30

T 200

T 622

CSAH 51

CSAH 30

CR 214

T 212

CSAH 23

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