County profile · official public datasets

Grant County, ND

60 public highway bridges tracked in the FHWA National Bridge Inventory: 45% rated Good, 45% Fair, 10% Poor.

60
Public bridges: 45%
Good condition: 10%
Poor condition

The verdict

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

Grant County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

32nd
of 53 on Poor share: 10%
Poor-condition share: 60
public highway bridges: 1968
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 #32 of 53 North Dakota counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 10%). Grant County, North Dakota contains 60 public highway bridges. Roughly 45% are rated “Good,” 45% “Fair,” and 10% “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

Public highway bridges in Grant County

Good condition

45%

27 of 60 rated 7-9

Fair condition

45%

27 of 60 rated 5-6

Poor condition

10%

6 of 60 rated 4 or below

In-state Poor-share rank

#32 of 53

Among North Dakota counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 60 NBI-tracked bridges by lowest applicable component rating.

Good

45% (27)

Fair

45% (27)

Poor

10% (6)

Grant County's Poor-condition bridges carry 460 vehicle crossings a day

That is 6.3% of the county's reported daily bridge traffic on 10% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 77 crossings a day against 117 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 60 of 60 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

68.3% of Grant County's bridges have passed the 50-year mark

41 of the 60 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 45% 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 84.8% of the county's Poor-condition bridge traffic

ND HIGHWAY 31 over DOG TOOTH CREEK, built 1957, carries 390 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 460 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

1
1930s

5
1940s

10
1950s

10
1960s

8
1970s

9
1980s

5
1990s

3
2010s

8
2020s

1

What this shows Construction peaked in the 1940s, when 10 of the county's bridges still in the inventory were built, which is 16.7% of those with a recorded year. That cohort is now 75 to 84 years old in the 2024 inventory. Its average build year is 1968, 7 years older than the North Dakota average of 1975.

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

The 5 North Dakota counties nearest Grant County in number of bridges, with their condition splits. Its 10% Poor share is the 3rd-lowest of these 6. Its average build year of 1968 against a peer-group mean of 1973 is 5 years older.

Showing the 5 closest of 52 North Dakota counties eligible for comparison.

Bridge inventory size and condition shares for Grant County and the 5 North Dakota counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Hettinger County	64	34.4%	50%	15.6%	1963
Billings County	60	61.7%	35%	3.3%	1979
LaMoure County	60	48.3%	40%	11.7%	1972
Grant County (this page)	60	45%	45%	10%	1968
Towner County	58	34.5%	39.7%	25.9%	1978
McLean County	57	40.4%	54.4%	5.3%	1973

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 North Dakota so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside ND (60 bridges here).

Hamilton County, FL · 60 bridges
Hernando County, FL · 60 bridges
Madison County, FL · 60 bridges
Heard County, GA · 60 bridges

Similar average build year

Nearest mean year-built outside ND (1968 here).

Montgomery County, PA · avg 1968 · 828 bridges
San Joaquin County, CA · avg 1968 · 644 bridges
Providence County, RI · avg 1968 · 476 bridges
Imperial County, CA · avg 1968 · 444 bridges

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

All 60 Good 27 Fair 27 Poor 6

Good-condition bridges (27)

Sort:

Grant County Bridge Snapshot

Condition distribution

Grant County's Poor-condition bridges carry 460 vehicle crossings a day

68.3% of Grant County's bridges have passed the 50-year mark

One structure carries 84.8% of the county's Poor-condition bridge traffic

How Grant County compares with North Dakota'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 (27)

61ST STREET SW

58th AVE SW

COUNTY HIGHWAY

HEIL ROAD

61st AVE SW

61ST AVE SW

64th ST SW

82ND ST SW

77th Ave SW

47TH AVENUE SW

COUNTY HIGHWAY

58th St SW

ND HIGHWAY 49

68th ST SW

IRRSR COUNTY HIWAY

IRRSR COUNTY HIWAY

IRRSR ND HIWAY 49

IRRSR ND HIWAY 31

IRRSR ND HIWAY 49

COUNTY HIGHWAY

COUNTY HIGHWAY

ND HIGHWAY 49

COUNTY HIGHWAY

ND HIGHWAY 49

COUNTY HIGHWAY

49TH AVENUE

85th St SW

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