U.S. Route 18 in Iowa

U.S. Highway 18
Route information
Maintained by Iowa DOT
Length:	311.459 mi[1] (501.245 km)
Existed:	November 11, 1926[2] – present
History:	Primary Road 19 from 1920–1926[3] National Parks Pike registered in 1920[4]
Major junctions
West end:	US 18 near Canton, S.D.
	US 75 near Hull Iowa 60 at Sheldon US 71 at Spencer US 169 at Algona I-35 at Clear Lake US 218 at Charles City US 63 at New Hampton US 52 at Postville
East end:	US 18 / WIS 60 at McGregor
Location
Counties:	Lyon Sioux O'Brien Clay Palo Alto Kossuth Hancock Cerro Gordo Floyd Chickasaw Fayette Clayton Allamakee
Highway system
United States Numbered Highway System List Special Divided Replaced Iowa Primary Highway System Interstate U.S. State Secondary Scenic ← Iowa 17 US 20 →

U.S. Highway 18 (US 18) is the northernmost east–west U.S. Highway in the state of Iowa. As with all state highways in Iowa, it is maintained by the Iowa Department of Transportation (Iowa DOT). It enters the state by crossing the Big Sioux River between Inwood and Canton, South Dakota. It travels 311 miles (501 km) and connects Spencer, Mason City and Charles City. The highway leaves the state via the Marquette–Joliet Bridge over the Mississippi River at Marquette. Prior to becoming a U.S. Highway, the route US 18 follows was known as Primary Road No. 19 and the National Parks Pike.

Route description

US 18 begins at the Big Sioux River approximately 2 miles (3.2 km) east of Canton, South Dakota. It runs easterly through rural Lyon County, in the northwestern corner of the state. At Inwood it meets Iowa 182, which provides access to Sioux Falls, South Dakota, via Iowa 9 and South Dakota Highway 42. US 18 turns south at Inwood and heads into Sioux County. The highway crosses the Rock River on its way towards Rock Valley and Hull. West of Hull, at Perkins, US 18 juts to the south along US 75 before turning east again closer to Hull. The highway continues east towards Sheldon.^[5]

As it crosses into O'Brien County on the western edge of Sheldon, US 18 intersects the business loop of Iowa 60. The two routes head east towards a diamond interchange with Iowa 60 on the eastern side of town where the business loop ends. The highway roughly parallels the Dakota, Minnesota and Eastern Railroad (DM&E Railroad). In Sanborn, US 18 is briefly overlapped by US 59, which joins from the north and leaves to the south. Continuing east, it passes through Hartley and then enters Clay County. North of Spencer, it intersects US 71 and the two routes head south together through town. On the south side of Spencer, the two routes come to a T intersection and each route heads in the opposite direction – US 18 to the east and US 71 to the west.^[5]

East of Spencer, US 18 passes through Ruthven in Palo Alto County. Between Ruthven and Emmetsburg, it is joined by Iowa 4 from the north. The two routes split again in Emmetsburg as Iowa 4 heads south. US 18 continues east, briefly heading south to enter Cylinder. The route curves back to the east at the DM&E Railroad line. An intersection with Iowa 15 near Whittemore marks the Palo Alto–Kossuth county line. Iowa 15 follows US 18 for 1 mile (1.6 km) before it splits away to the north. On the northern edge of Algona, the highway meets US 169. At the eastern county line, shared with Hancock County, is an intersection with Iowa 17, which marks that route's northern end.^[5]

In Hancock County, the route passes through Britt before meeting US 69 1 mile (1.6 km) west of Garner; the two highways split in Garner. East of Garner, the route takes a north-northeasterly path as it goes through Ventura and skirts the northern shore of Clear Lake. Near the northeastern shore of the lake, it enters the city of Clear Lake, where it meets Interstate 35 (I-35). Iowa 122 and U.S. Route 18 Business (US 18 Bus.) head east from the interchange with the interstate. US 18 traffic follows southbound I-35 for 4 miles (6.4 km). Iowa 27, the Avenue of the Saints highway, which had hitherto followed I-35 southbound now follows US 18 eastbound. The two routes, now on a four-lane, controlled-access highway, follow a path which passes to the south of Mason City. They meet US 65 and US 18 Bus. at exit 186.^[5]

US 18 / US 218 / Iowa 27 pass a wind farm near Charles City

At the Floyd county line, US  and Iowa 27 become a limited-access road and angle slightly to the northeast, passing Rudd. At Floyd, the two routes are joined by US 218. The three routes head south along a bypass of Charles City. They intersect Iowa 14 on the western side of town and take a 90-degree curve to the east. At exit 218 of the expressway, US 18 leaves US 218 and Iowa 27, which continue southeastward towards Cedar Falls–Waterloo. US 18 briefly heads north into Charles City with US 218 Bus.. The two routes meet the northern end of Iowa 14, and US 18 splits away to the east to cross the Cedar River.

Heading east again, the route enters Chickasaw County and passes through Bassett on its way to New Hampton. It meets US 63 at a four-lane bypass on the western side of town. The two routes head south for 8 miles (13 km), splitting at the mile 196 interchange which is also the eastern end of Iowa 346. The route turns to travel due-east through Fredericksburg.^[5]

US 18 crosses into Wisconsin via the Marquette–Joliet Bridge

Continuing due-east, US 18 does not enter another community for 20 miles (32 km) until it reaches West Union in Fayette County. In West Union, it intersects Iowa 150. East of town, it crosses into the Driftless Area, an area that was untouched by glaciation during the last ice age. The route turns to the northeast to through Clermont and then to the north to meet US 52 at Postville in southern Allamakee County. The two routes head east through Postville and turn south into Clayton County. Near Froelich, US 52 leaves to the south towards Dubuque. Heading to the northeast towards, McGregor and Marquette, its business loop goes through the towns while the mainline skirts around them. The business loop rejoins the mainline at the foot of the Marquette–Joliet Bridge, which spans the Mississippi River.^[5] US 18 continues east into Wisconsin with Wisconsin Highway 60, which begins at the state line.^[6]

History

Before it and the rest of the U.S. Highway System were designated on November 11, 1926, US 18 was known by two names in the state. It was first known as Primary Road No. 19, which was assigned to the route when the Iowa State Highway Commission published its first state highway map in 1919.^[7] The route was also called the National Parks Pike, which began at Yellowstone National Park and ended in Madison, Wisconsin, encompassing all of Primary Road No. 19 in the state. The Pike was registered with the on April 29, 1920.^[4] The National Parks Pike name fell into disuse after the highway became US 18.^[8]

By 1927, a significant portion of the route was paved, while the remainder was gravelled. All of O'Brien County and 80 miles (129 km) between Algona and Charles City were paved.^[9] In seven years, the gap between O'Brien County and Algona was finished which created 160 miles (257 km) of continuous pavement. During those same seven years, the route from West Union to the Mississippi River and all of Primary Road No. 59, which included the 7-mile-long (11 km) overlap of US 18 near New Hampton were paved.^[10] Primary Road No. 59 is now known as US 63. By the start of World War II, the only remaining section of US 18 that wasn't paved was an 11-mile (18 km) section west of Rock Valley in Sioux County.^[11] That last section would not be completed for another ten years.^[12]

US 18 passing through McGregor in 1975

Prior to 1932, the only way vehicles traveling US 18 could cross the Mississippi River was by ferry. That changed in when identical suspension bridges were built to cross the river between Marquette and Prairie du Chien, Wisconsin. Built in 1931–1932, each bridge was 450 feet (140 m) long and crossed a main channel of the river and were divided by a 2,000-foot-long (610 m) island causeway. The first car to cross the bridges did so on March 7, 1932. Users of the bridge had to pay a toll until July 15, 1954. The bridges remained in use for another twenty years, when they were replaced by the Marquette–Joliet Bridge.^[13] In 1988–89, a bypass was built around McGregor so US 18 could connect directly to the Marquette–Joliet Bridge. A short road had previously provided access to and from the bridge. The old alignment of the route became US 18 Bus.^[14]

Over the late-1990s, construction began on the Avenue of the Saints corridor near Mason City. A new controlled-access facility was built south of the city east to Rudd.^[5] On December 5, 1999, this section of freeway opened and US 18 was realigned onto the new road. The old alignment became Iowa Highway 122. By the end of the next year, the four-lane expressway was extended to Charles City.^[15] By 2003, an expressway carrying US 63 was built around New Hampton. US 18 was rerouted onto the expressway and the western end of Iowa 24 was moved to the US 63 / US 18 interchange.^[16]

Major intersections

County	Location	mi[1]	km	Exit[5]	Destinations	Notes
Big Sioux River		0.000	0.000		US 18 west – Canton	Continuation into South Dakota
				South Dakota–Iowa state line
Lyon	Inwood	4.974	8.005		Iowa 182 north to Iowa 9
Sioux	Lincoln Township	24.835	39.968		US 75 north – Rock Rapids	Western end of US 75 overlap
		25.833	41.574		US 75 south – Sioux Center	Eastern end of US 75 overlap
O'Brien	Sheldon	41.164	66.247		Iowa 60 Business south (2nd Avenue)	Western end of Iowa 60 Business overlap
		44.250	71.213		Iowa 60 / Iowa 60 Business ends – Worthington, Minn., Sioux City	Eastern end of Iowa 60 Business overlap
	Sanborn	52.785	84.949		US 59 north – Worthington, Minn.	Western end of US 59 overlap
	Franklin Township	53.782	86.554		US 59 south – Primghar	Eastern end of US 59 overlap
Clay	Spencer	77.724	125.085		US 71 north – Milford	Western end of US 71 overlap
		81.740	131.548		US 71 south – Storm Lake	Eastern end of US 71 overlap
Palo Alto	Emmetsburg Township	101.290	163.010		Iowa 4 north – Graettinger	Western end of Iowa 4 overlap
	Emmetsburg	106.058	170.684		Iowa 4 south (Broadway Street) – Pocahontas	Eastern end of Iowa 4 overlap
	Fern Valley Township	119.682	192.610		Iowa 15 south – West Bend	Western end of Iowa 15 overlap
Kossuth	Lotts Creek Township	120.670	194.200		Iowa 15 north – Fenton	Eastern end of Iowa 15 overlap
	Algona	130.124	209.414		US 169 – Algona, Bancroft
	Wesley Township	143.843	231.493		Iowa 17 south – Corwith
Hancock	Garfield Township	160.860	258.879		US 69 north – Forest City	Western end of US 69 overlap
	Garner	161.950	260.633		US 69 south – Belmond	Eastern end of US 69 overlap
Cerro Gordo	Clear Lake	175.393	282.268	194	I-35 north / Iowa 27 north / US 18 Business east / Iowa 122 east – Minneapolis, Mason City	Western end of I-35 / Iowa 27 overlap
		176.263	283.668	193	CR B35 (4th Avenue South)
	Lake Township	178.712	287.609	190	I-35 south – Des Moines	Eastern end of I-35 overlap
		183.163	294.772	183	Airport, Eisenhower Avenue
	Mason City	186.173	299.616	186	US 65 / US 18 Business west – Downtown Mason City, Rockwell
	Portland Township	190.225	306.137	190	CR S56 (California Avenue)
		195.362	314.405	195	CR S70 – Nora Springs
Floyd	Floyd	210.059	338.057		US 218 north – Floyd, Osage	North end of US 218 overlap
	Floyd Township	212.476	341.947	212	US 218 Business / CR B35 – Charles City
	Saint Charles Township	214.600	345.365	214	Iowa 14 – Charles City, Greene
	Charles City	218.176	351.120	218	US 218 south / Iowa 27 south / US 218 Business north – Charles City, New Hampton	Western end of US 218 Business overlap
		220.007	354.067		US 218 Business north / Iowa 14 south	Eastern end of US 218 Business overlap
Chickasaw	New Hampton	237.531	382.269	204	US 63 north / Iowa 24 east – New Hampton, Lime Springs	Western end of US 63 overlap
	New Hampton Township	240.164	386.506	201	225th Street – New Hampton
	Dresden Township	244.668	393.755	196	US 63 south / Iowa 346 west – Nashua, Waterloo	Eastern end of US 63 overlap
Fayette	West Union	270.183	434.817		Iowa 150 to Iowa 56 – Fayette, Calmar
Clayton	No major junctions
Allamakee	Post Township	286.753	461.484		US 52 north – Calmar	Western end of US 52 overlap
	Postville	287.817	463.197		Iowa 51 north (N. Lawler Street)
Clayton	Giard Township	303.104	487.799		US 52 south – Guttenberg	Eastern end of US 52 overlap
	Mendon Township	307.573	494.991		US 18 Business east / Iowa 76 north – McGregor
	Marquette	311.176	500.789		US 18 Business west / Iowa 76 – Marquette, McGregor
Mississippi River		311.459	501.245	Marquette–Joliet Bridge; Iowa–Wisconsin state line
					US 18 east / WIS 60 begins – Prairie du Chien	Continuation into Wisconsin
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus

See also

• Special routes of U.S. Route 18

References

External links

Route map: Google

• The Iowa Highways Page by Jason Hancock
• Twin Suspension Bridges Historic photos of the former river crossing at Marquette by John A. Weeks

U.S. Route 18
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