Iowa Highway 175 is a main east–west route in the northern portion of the state. The highway has a length of. Iowa Highway 175 enters the state by a Missouri River crossing between Decatur, Nebraska and Onawa. The highway continues westward as Nebraska Highway 51. Iowa 175's eastern terminus is at a T intersection with U.S. Route 63 in southwestern Black Hawk County. Despite Iowa 175's length, it only passes through small communities. The largest city on the route is Onawa, whose 2000 population was 3,091.
Route description
Iowa Highway 175 begins at the eastern end of the Burt County Missouri River Bridge west of Onawa. At Onawa, it intersects Interstate 29. At Turin, it meets Iowa Highway 37 and turns northeast to follow an alignment which lies next to the Maple River. It continues through Castana and meets Iowa Highway 141 in Mapleton. At Mapleton, Iowa 175 overlaps Iowa Highway 141 through town. This is a wrong-way concurrency, with eastbound Iowa 175 and westbound Iowa 141 routed on one side of the road, and vice versa. It continues northeast from Mapleton through Danbury and Battle Creek and meets U.S. Highway 59 west of Ida Grove. After passing through Ida Grove together with U.S. 59, they separate east of Ida Grove. Iowa 175 passes east through Arthur and at Odebolt, meets Iowa Highway 39. Further east, Iowa 175 meets U.S. Highway 71. Iowa 175 and U.S. 71 run east, then south, then east again concurrently through Lake View and Ulmer before separating at Auburn. Iowa 175 leaves Auburn going east, then passes through Lake City. After Lake City, Iowa 175 meets Iowa Highway 4. The two highways run concurrently through Lohrville before separating. Iowa 175 then passes through Farnhamville and Gowrie and intersects Iowa Highway 144 before intersecting U.S. Highway 169 at Harcourt. They continue east together before separating before Dayton. After passing through Stratford, Iowa 175 meets Iowa Highway 17 at Stanhope. It leaves Stanhope going east and meets U.S. Highway 69 south of Jewell. They run together going north into Jewell before Iowa 175 turns east. After passing through Ellsworth, Iowa 175 intersects Interstate 35. Iowa Highway 175 then continues east of I-35 by passing through Radcliffe before meeting U.S. Highway 65 in Hubbard. Iowa 175 and U.S. 65 then go north, then east, together before separating. Iowa 175 then goes east through Eldora and meets Iowa Highway 14 west of Grundy Center. Iowa 175 continues east with Iowa 14 before separating in Grundy Center. It turns slightly southeasterly while passing through Morrison and Reinbeck, then turns east and ends at U.S. Highway 63 south of Hudson.
History
Iowa Highway 175 was originally designated in 1930 as a very short spur from U.S. Route 65 to Hubbard but extended west to Stratford by 1937. Iowa 175 extended west to Auburn in October 1940, replacing Iowa 91, a spur route from Dayton to US 169, Iowa 47, a spur route from US 169 to Farnhamville, Iowa 287, a spur route from Farnhamville to Iowa 17, and Iowa 188, which went from Iowa 17 to Auburn. In January 1948, Iowa 175 extended west to US 75, replacing Iowa 35 and a duplex with Iowa 37 was created; Iowa 37 would be truncated to Iowa 175 on May 11, 1966. By 1955 Iowa 175 had extended westward to Nebraska, replacing Iowa 165. The final segment of Highway 175 was commissioned in 1969, extending the highway eastward from Hubbard to its present eastern terminus.
