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Irr Bia Rte 6 over Porcupine Creek

Sioux County, North Dakota · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

Irr Bia Rte 6 over Porcupine Creek in Sioux County, North Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
It was built in 1969, making it 56 years old at the 2025 inventory.
It carries about 173 vehicles a day (traffic count year 2023).
It is one of 9 of the 22 inventoried bridges in Sioux County rated fair (40.9%); 1 (4.5%) are rated poor.
A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.

Component ratings

Source: FHWA National Bridge Inventory, 2025 data as reported by the North Dakota department of transportation.

Bridge	Built	Vehicles/day	Condition
Irrsr Nd Hiway 24 over Beaver Holes Creek	1965	1,830	Fair
Irrsr Nd Hiway 24 over Porcupine Creek	1963	1,740	Fair
Irrsr Nd Hiway 24 over Battle Creek	1965	1,700	Fair
Irr Bia Rte 3 over Four Mile Creek Bridge	2010	1,000	Good
Irrsr Nd Hiway 24 over Four Mile Creek	1930	750	Fair
Irr Bia Rte 29 over One Mile Creek	1950	401	Poor