Bridge conditions in Tripp County, South Dakota

89 inventoried bridges · 22 rated poor · 2025 National Bridge Inventory

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

Tripp County has 22 bridges rated poor out of 89 inventoried, a 24.7% share that puts it well above the national rate of about 7%.

22 of the 89 bridges in Tripp County, South Dakota, are rated in poor condition (24.7%) in the 2025 National Bridge Inventory, as of August 20, 2026.
29 bridges (32.6%) are rated good and 38 (42.7%) fair.
The median Tripp County bridge was built in 1969.
The busiest poor-rated bridge is SD049 over Ck (built 1972), carrying about 502 vehicles a day.

Good 32.6% · Fair 42.7% · Poor 24.7% of 89 bridges

Bridges rated poor

Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.

Bridge	Built	Vehicles/day	Condition
SD049 over Ck	1972	502	Poor
277 Street over Old Lodge Ck	1950	100	Poor
300 Street over Sand Ck	1967	55	Poor
277 Street over Dog Ear Ck	1930	55	Poor
287 Street over Ck	1935	55	Poor
279 Street over West Br Bull Ck	1955	55	Poor
271 Street over Cottonwood Ck	1945	50	Poor
266 St Ideal Road over Owl Ck	1955	50	Poor
266 St Ideal Rd over Dog Ear Ck	1955	50	Poor
277 Street over Dog Ear Ck	1940	50	Poor
292 Street over Willow Ck	1950	46	Poor
269 Street over Old Lodge Ck	1955	40	Poor
318 Avenue over Old Lodge Ck	1958	37	Poor
329 Avenue over West Br Bull Ck	1950	35	Poor
300 Street over Shady Ck	1966	31	Poor
311 Avenue over Dog Ear Ck	1963	31	Poor
318 Avenue over Old Lodge Ck	1987	31	Poor
268 Street over Old Lodge Ck	1960	31	Poor
280 Street over Thunder Ck	1962	31	Poor
301 Street over Rock Bridge Creek	1958	31	Poor
300 Avenue over Sand Ck	1965	29	Poor
324 Avenue over Mocassin Ck	1924	20	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
US018 over Dog Ear Ck	1965	3,553	Fair
US018 Ser Rd over Ck	1965	2,820	Fair
US018 over Sand Ck	1973	2,052	Fair
US018 over Ck	1973	1,803	Fair
US018 over Cottonwood Ck	1965	1,746	Fair
US018 over Big Hollow Ck	1965	1,746	Good
SD044 over Sand Ck	1969	1,172	Fair
SD044 over Thunder Ck	1969	1,172	Good
US018 over De Bell Ck	1988	1,139	Fair
US018 over West Cottonwood Ck	1988	1,139	Fair

Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.

All of South Dakota: South Dakota bridge conditions by county · every download on the data page.

Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.