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Bridge conditions in Charles Mix County, South Dakota

103 inventoried bridges · 24 rated poor · 2025 National Bridge Inventory

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

About one in 4 bridges in Charles Mix County is rated in poor condition: 24 of 103 on the federal inventory, one of the higher shares in South Dakota.

24 of the 103 bridges in Charles Mix County, South Dakota, are rated in poor condition (23.3%) in the 2025 National Bridge Inventory, as of August 20, 2026.
39 bridges (37.9%) are rated good and 40 (38.8%) fair.
The median Charles Mix County bridge was built in 1970.
The busiest poor-rated bridge is 30010 400TH Avenue over Choteau Creek (built 1958), carrying about 205 vehicles a day.

Good 37.9% · Fair 38.8% · Poor 23.3% of 103 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
30010 400TH Avenue over Choteau Creek	1958	205	Poor
27720 363RD Avenue over Platte Creek	1977	48	Poor
36460 276TH Street over Platte Creek	1936	48	Poor
27180 369TH Avenue over Platte Creek	1940	48	Poor
37570 287 Street over Pease Ck	1920	48	Poor
37590 286TH Street over Pease Creek	1974	48	Poor
38080 291ST Street over Creek	1935	48	Poor
29470 381ST Avenue over Creek	1979	48	Poor
38450 292ND Street over Creek	1935	48	Poor
28870 385TH Avenue over Creek	1945	48	Poor
38710 294TH Street over Creek	1930	48	Poor
38890 286TH Street over Andes Creek	1930	48	Poor
38930 302 St over Ck	1941	48	Poor
30410 390 Ave over Mosquito Ck	1941	48	Poor
30480 391ST Street over Mosquito Creek	1974	48	Poor
39120 305TH Street over Mosquito Creek	1920	48	Poor
29110 393RD Avenue over Creek	1925	48	Poor
39460 289TH Street over Creek	1940	48	Poor
39540 287TH Street over Choteau Creek	1940	48	Poor
29620 396TH Avenue over Choteau Creek	1930	48	Poor
39740 296TH Street over Creek	1912	48	Poor
39450 292ND Street over Choteau Creek	1974	40	Poor
294TH Street over Garden Ck	1940	20	Poor
29120 383RD Avenue over Drainage Ditch	1930	4	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
SD045 over Drainage Channel	1994	3,934	Good
SD044 over Platte Ck	1964	2,420	Fair
SD044 over Castalia Ck	1963	1,538	Good
Irr US018 over Saint Francis Bay	2023	1,494	Good
Irr SD050 over Trib Choteau Ck	2020	1,329	Good
Old Irr SD050 over Ck	1940	1,329	Fair
Irr US018 over Lake Andes Outlet	2005	1,298	Good
Irr US018 over Trib to Lake Andes	2005	1,298	Good
Irr SD046 over Ck	1968	1,199	Fair
Irr SD046 over Choteau Ck	1968	1,199	Good

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

Every bridge in Charles Mix County → - all 103, busiest first, each with its own condition record.

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.