Iowa Highway 12

Iowa Highway 12 (Iowa 12) is a 46.212-mile-long (74.371 km) state highway that runs from north to south in northwestern Iowa. The highway begins in eastern Sioux City at U.S. Highway 20 (US 20) and US 75. For the first seven and a half miles (12.1 km) of the route, Iowa 12 is an unsigned highway. The first five miles (8.0 km) are signed only as U.S. Highway 20 Business; the other two and a half miles (4.0 km) are overlapped by Interstate 29 (I-29). From here, the highway lies just east of the Big Sioux River, which separates Iowa from South Dakota. The northern end of Iowa 12 is in Hawarden at an intersection with Iowa 10.

Iowa Highway 12
Iowa 12 highlighted in red
Route information
Maintained by Iowa DOT
Length	46.212 mi[1] (74.371 km)
Existed	1920–present
Tourist routes	Loess Hills Scenic Byway
Major junctions
South end	US 20 / US 75 at Sioux City
	I-29 / US 77 at Sioux City Iowa 3 between Westfield and Akron
North end	Iowa 10 in Hawarden
Location
Counties	Woodbury Plymouth Sioux
Highway system
Iowa Primary Highway System Interstate U.S. State Secondary Scenic ← Iowa 10 → Iowa 13

Route description

Stone State Park is along Iowa 12

Iowa Highway 12 begins at U.S. 20 and U.S. 75 signed as Business US 20. It continues west through Sioux City and becomes concurrent with Interstate 29 going west to Riverside Boulevard, where signage begins. It follows Riverside Boulevard while it passes through the Riverside neighborhood in Sioux City. It passes past Stone State Park in northwestern Sioux City and continues northwest towards Westfield. It turns northeast to enter Westfield, then intersects Iowa Highway 3. Iowa 12 and Iowa 3 overlap and go northeast to Akron, where Iowa 3 turns east. Iowa 12 continues northeast through Chatsworth and ends at Iowa 10 in Hawarden.

History

Iowa Highway 12 was designated as a state highway in 1920. It originally went between Hamburg and Akron. It was shortened to Missouri Valley in 1924, and Sioux City in 1926. In 1931, it was extended north to Hawarden. In 1958, it was shortened to its intersection with I-29, but then in 1979, was extended east along I-29 and the newly formed Business Route 20 to end at the new U.S. 20 bypass in eastern Sioux City. In 2000, signage for this extension was removed and signage for Iowa 12 ended at I-29, though officially, Iowa 12 continues east through Sioux City.

Major intersections

County	Location	mi	km	Exit	Destinations	Notes
Woodbury	Concord–Woodbury township line	0.000	0.000		US 20 Business begins / US 20 / US 75 – South Sioux City	Southern terminus; southern end of US 20 Business overlap; US 75 south exit 93, US 20 east exit 4B
	Sioux City	3.269	5.261		US 75 Business (Lewis Boulevard)	Interchange
					I-29 south	Southern end of I-29 overlap; I-29 exit 147
		4.723	7.601	148	US 77 south (US 20 Business west) / Wesley Parkway north – South Sioux City Nebr.	Exit numbers follow I-29; southern end of US 20 Business overlap; southbound access via exit 149
		5.311	8.547	149	To US 77 south (US 20 Business west) / Hamilton Boulevard – Riverfront Wesley Parkway north – South Sioux City	Northbound signed as Hamilton Boulevard only
		7.527	12.114		I-29 north – Sioux Falls	Northern end of I-29 overlap; I-29 exit 151; IowaDOT signs this as southern end of Iowa 12
Plymouth	Westfield Township	28.359	45.639		Iowa 3 west – Vermillion S.D.	Southern end of Iowa 3 overlap
	Akron	33.094	53.260		Iowa 3 east (South Street) / Loess Hills Scenic Byway ends – Le Mars	Northern end of Iowa 3 overlap
		33.861	54.494		Big Sioux River Road to I-29 / SD 48 – Alcester
Sioux	Hawarden	46.212	74.371		Iowa 10 – Beresford SD, Orange City	Northern terminus; road continues as Iowa 10 west (Avenue E north)
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus

References

1. 2014 Volume of Traffic on the Primary Road System of Iowa (PDF) (Report). Iowa Department of Transportation. January 1, 2014. Retrieved July 17, 2015.