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Bridge conditions in Plymouth County, Iowa

430 inventoried bridges · 90 rated poor · 2025 National Bridge Inventory

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

Plymouth County has 90 bridges rated poor out of 430 inventoried, a 20.9% share that puts it well above the national rate of about 7%.

90 of the 430 bridges in Plymouth County, Iowa, are rated in poor condition (20.9%) in the 2025 National Bridge Inventory, as of August 20, 2026.
233 bridges (54.2%) are rated good and 107 (24.9%) fair.
The median Plymouth County bridge was built in 1978.
The busiest poor-rated bridge is US 75 over Stream (built 1926), carrying about 14,000 vehicles a day.

Good 54.2% · Fair 24.9% · Poor 20.9% of 430 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
US 75 over Stream	1926	14,000	Poor
FM over Stephens Creek	1960	628	Poor
FM K-42 over Carter Creek	1941	190	Poor
FM K-42 over Carter Creek	1966	190	Poor
FM C-43 over Broken Kettle Creek	1960	159	Poor
150TH St over Floyd River	1954	131	Poor
165TH St over West Branch Floyd River	1911	120	Poor
Lone Tree Rd over Perry Creek	1953	71	Poor
160TH St over Deep Creek	1900	71	Poor
200TH St over W.branch Floyd River	1960	71	Poor
Tamarack Ave over Drainage Ditch	1948	60	Poor
330TH St over Creek	1956	60	Poor
Polk Ave over Deep Creek	1958	60	Poor
Local over Willow Creek	1941	60	Poor
Quartz Ave over Willow Creek	1946	60	Poor
140TH St over Floyd River	1954	60	Poor
Lynx Ave over Big Whiskey Creek	1958	50	Poor
300TH St over Mud Creek	1950	50	Poor
190TH St over Bull Run	1961	50	Poor
Shamrock Ave over Deep Creek	1953	50	Poor
Juniper Ave over Mink Creek	1900	45	Poor
Lynx Ave over Muddy Creek	1949	34	Poor
260TH St over Dry Branch	1956	34	Poor
170TH St over Drainage	1900	34	Poor
200TH St over Mink Creek	1949	34	Poor
200TH St over Mink Creek	1953	34	Poor
Juniper Ave over Mink Creek	1948	34	Poor
Iris Ave over Mink Creek	1900	34	Poor
Granite Ave over Broken Kettle Creek	1900	34	Poor
310TH St over Creek	1900	30	Poor
320TH St over Creek	1900	30	Poor
Local over Drainage	1955	30	Poor
230TH St over Rathburn Creek	1900	30	Poor
Pioneer Ave over Deep Creek	1917	30	Poor
Fir Ave over Broken Kettle Creek	1900	30	Poor
Fawn Ave over Drainage	1900	30	Poor
Fir Ave over Bull Run	1948	30	Poor
200TH St over Drainage	1959	30	Poor
140TH St over Drainage	1961	30	Poor
Noble Ave over Deep Creek	1953	30	Poor
280TH St over Mud Creek	1900	26	Poor
300TH St over Johns Creek	1900	26	Poor
310TH St over Dry Branch	1941	26	Poor
Quest Ave over Rathburn Creek	1950	26	Poor
Lynx Ave over Plymouth Creek	1960	26	Poor
220TH St over Drainage	1958	26	Poor
Impala Ave over Mink Creek	1938	26	Poor
190TH St over Westfield Creek	1951	26	Poor
150TH St over Broken Kettle Creek	1952	26	Poor
Diamond Ave over Beaver Creek	1900	26	Poor
280TH St over Perry Creek	1900	20	Poor
Sunset Ave over Dd	1956	20	Poor
190TH St over Drainage	1949	20	Poor
180TH St over Westfield Creek	1948	20	Poor
Bluebird Ave over Drainage	1949	20	Poor
120TH St over W Br Floyd River	1941	20	Poor
130TH St over W Br Floyd River	1900	20	Poor
130TH St over Drainage	1961	20	Poor
Evergreen Ave over Indian Creek	1900	20	Poor
Granite Ave over Broken Kettle Creek	1959	20	Poor
140TH St over Broken Kettle Creek	1948	20	Poor
140TH St over Indian Creek	1956	20	Poor
120TH St over Indian Creek	1900	20	Poor
Roosevelt Ave over W F Little Sioux	1900	15	Poor
Roosevelt Ave over Dd	1900	15	Poor
Ritchie Rd over Mud Creek	1948	15	Poor
190TH St over Mink Creek	1947	15	Poor
Otter Ave over Willow Creek	1949	15	Poor
120TH St over Indian Creek	1900	15	Poor
235TH St over Broken Kettle Ck	1900	15	Poor
300TH St over Creek	1956	11	Poor
280TH St over Dry Branch	1900	11	Poor
320TH St over Mud Creek	1900	11	Poor
320TH St over Big Whiskey Creek	1900	11	Poor
240TH St over Big Whiskey Slough	1953	11	Poor
260TH St over Johns Creek	1900	11	Poor
260TH over Johns Creek	1966	11	Poor
270TH St over Carter Creek	1900	11	Poor
Fawn Ave over Broken Kettle Creek	1953	11	Poor
Evergreen Ave over Drainage	1900	11	Poor
Diamond Ave over Westfield Creek	1900	11	Poor
Concord Ave over Unnamed Creek	1949	11	Poor
Local over Deep Creek	1941	11	Poor
150TH St over Broken Kettle Creek	1952	11	Poor
240TH St over Mud Creek	1956	5	Poor
240TH St over Perry Creek	1900	5	Poor
Granite Ave over Perry Creek	1952	5	Poor
200TH St over Clear Creek	1946	5	Poor
Marble Ave. over Plymouth Creek	1946	5	Poor
Evergreen Ave over Indian Creek	1961	5	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
US 75 over Stream	1999	18,200	Fair
US 75 over Stream	2019	14,900	Good
US 75 over Stream	2019	14,900	Good
US 75 over Stream	2019	14,900	Good
US 75 over Stream	2019	14,900	Good
US 75 over Stream	1926	14,000	Poor
US 75 over Dry Creek	2023	14,000	Good
US 75 over Dry Creek	2023	14,000	Good
US 75 over Dry Creek	2023	14,000	Good
US 75 over Drainage Ditch	2023	14,000	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 Plymouth County → - all 430, 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.