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Bridge conditions in Monona County, Iowa

160 inventoried bridges · 41 rated poor · 2025 National Bridge Inventory

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

About one in 4 bridges in Monona County is rated in poor condition: 41 of 160 on the federal inventory, one of the higher shares in Iowa.

41 of the 160 bridges in Monona County, Iowa, are rated in poor condition (25.6%) in the 2025 National Bridge Inventory, as of August 20, 2026.
60 bridges (37.5%) are rated good and 59 (36.9%) fair.
The median Monona County bridge was built in 1970.
The busiest poor-rated bridge is Ia 175 over I-29 (built 1959), carrying about 4,090 vehicles a day.

Good 37.5% · Fair 36.9% · Poor 25.6% of 160 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
Ia 175 over I-29	1959	4,090	Poor
Ia 141 & 175 over Maple River	1967	3,720	Poor
FM over Diversion Ditch	1962	597	Poor
FM over Dd	1959	597	Poor
FM over Famers Garretson Ditch	1962	578	Poor
FM over Soldier River	1955	349	Poor
FM over Haitz Dd	1961	229	Poor
FM over West Fork Dd	1961	229	Poor
FM over Willow Creek	1979	199	Poor
FM over Jordan Creek	1958	159	Poor
FM over Soldier Creek	1949	159	Poor
FM over Little Sioux River	1925	159	Poor
FM over Maple River	1960	150	Poor
FM over Little Sioux River	1961	150	Poor
FM over Little Sioux River	1960	131	Poor
Local over Stream	1973	80	Poor
FM over Nagel Dd	1960	79	Poor
FM over Stream	1956	71	Poor
FM over Jordan Creek	1954	60	Poor
Local over Stream	1900	60	Poor
FM over NE Norway Creek	1949	50	Poor
FM over Little Sioux River	1960	45	Poor
Local over Monona Harrison Dd	1959	45	Poor
FM over Sioux River	1960	45	Poor
Local over West Fork Dd	1961	45	Poor
FM over Willow Creek	1952	40	Poor
FM over Norway Creek	1953	40	Poor
FM over Soldier Creek	1948	40	Poor
Local over Mccandless Cleghorn Dd	1970	40	Poor
Local Road over Local Stream	1962	29	Poor
Local over Mccandless Cleghorn D D	1997	29	Poor
Local over Mccandless Cleghorn	1976	26	Poor
Local Road over Local Stream	1964	26	Poor
Local over Trib to Soldier River	1990	20	Poor
Local over Trib Maple River	1900	20	Poor
K53 Dogwood Ave over Mccandless Cleghorn	1970	20	Poor
Local over Jordan Creek	1912	15	Poor
Local over Willow Creek	1978	11	Poor
Local over Local Stream	1900	11	Poor
FM over Beaver Creek	1958	11	Poor
Local over Trib to Maple River	1900	5	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
NB I-29 over Robinson Ditch	2011	7,800	Good
SB I-29 over Robinson Ditch	2009	7,800	Good
NB I-29 over Cleghorn Creek	2012	7,250	Good
SB I-29 over Cleghorn Creek	2011	7,250	Good
Ia 175 over Mccandlesscleghorn Ditch	2023	5,300	Good
Ia 175 over I-29	1959	4,090	Poor
Ia 141 & 175 over Maple River	1967	3,720	Poor
Ia 175 over Drainage Ditch	1964	2,160	Fair
Ia 175 over Little Sioux River	1959	2,160	Fair
Ia 141 over Simmons Creek	2014	1,920	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 Monona County → - all 160, busiest first, each with its own condition record.

All of Iowa: Iowa 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.