U.S. Route 18 (US 18) is an east–west U.S. highway in the

Midwestern United States The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. I ...

. The western terminus is in

Orin, Wyoming Orin is a hamlet and the locus of a same-named census-designated place (CDP) in Converse County, Wyoming, United States. The population was 46 at the 2010 census. History The community was named for Orin Hughitt, the uncle of a railroad official ...

at an interchange with

Interstate 25 Interstate 25 (I-25) is a major Interstate Highway in the western United States. It is primarily a north–south highway, serving as the main route through New Mexico, Colorado, and Wyoming. I-25 stretches from I-10 at Las Cruces, New Mexi ...

. Its eastern terminus is in downtown

Milwaukee, Wisconsin Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee i ...

. However, US 18 runs concurrent with other U.S. routes from its western terminus to

Mule Creek Junction, Wyoming Mule Creek Junction is a former community in Niobrara County, Wyoming at the junction of US 18 and US 85. Geography The Junction is located on the southwest corner of the Black Hills The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼho ...

. US 18 is one of the original

United States highway The United States Numbered Highway System (often called U.S. Routes or U.S. Highways) is an integrated network of roads and highways numbered within a nationwide grid in the contiguous United States. As the designation and numbering of these hi ...

s of 1926. The US 18 designation was originally proposed for a road in

Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and t ...

from Grand Haven east to

Detroit Detroit ( , ; , ) is the largest city in the U.S. state of Michigan. It is also the largest U.S. city on the United States–Canada border, and the seat of government of Wayne County. The City of Detroit had a population of 639,111 at t ...

. This roadway was eventually designated as U.S. Route 16.

Route description

Wyoming

Wyoming Wyoming () is a state in the Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the southwest, and Colorado to t ...

, US 18 runs concurrent with U.S. Route 20 from

to Lusk, where US 18 branches off to run concurrently with

U.S. Route 85 U.S. Route 85 (US 85) is a north–south United States Highway that travels in the Mountain and Northern Plains states of the United States. The southern terminus of the highway is at the Mexican border in El Paso, Texas, connecting wi ...

. At the unincorporated community of Mule Creek Junction in northeastern Niobrara County, US 18 leaves US 85. This ten-mile (16 km) stretch from US 85 to the South Dakota border is the only segment of US 18 in Wyoming which is not co-signed with another highway. Running for nearly 100 miles, US 18 has a speed limit of 70 MPH with the exception of its ending terminus at Orin and the portion throughout Lusk.

South Dakota

U.S. 18 enters

South Dakota South Dakota (; Sioux: , ) is a U.S. state in the North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota and Dakota Sioux Native American tribes, who comprise a large po ...

west of Edgemont. It passes through

Hot Springs A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma (molten rock) or by circ ...

, the Pine Ridge Indian Reservation, the

Rosebud Indian Reservation The Rosebud Indian Reservation is an Indian reservation in South Dakota, United States. It is the home of the federally recognized Rosebud Sioux Tribe, who are Sicangu, a band of Lakota people. The Lakota name ''Sicangu Oyate'' translates as t ...

, Winner, and Gregory before crossing the Missouri River near Pickstown over the Fort Randall Dam. East of the Missouri River, U.S. 18 passes through (or near) Lake Andes and Tripp before a brief concurrency with

Interstate 29 Interstate 29 (I-29) is an Interstate Highway in the Midwestern United States. I-29 runs from Kansas City, Missouri, at a junction with I-35 and I-70, to the Canada–US border near Pembina, North Dakota, where it connects with Manitoba ...

near

Worthing Worthing () is a seaside town in West Sussex, England, at the foot of the South Downs, west of Brighton, and east of Chichester. With a population of 111,400 and an area of , the borough is the second largest component of the Brighton and Ho ...

. East of I-29, U.S. 18 passes through

Canton Canton may refer to: Administrative division terminology * Canton (administrative division), territorial/administrative division in some countries, notably Switzerland * Township (Canada), known as ''canton'' in Canadian French Arts and ente ...

before crossing the

Big Sioux River The Big Sioux River is a tributary of the Missouri River in eastern South Dakota and northwestern Iowa in the United States. It flows generally southwardly for ,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataTh ...

into Iowa. The Oyate Trail is one of the names given (in the late 1990s) to the section of US-18 traveling across

from

I-29 Interstate 29 (I-29) is an Interstate Highway in the Midwestern United States. I-29 runs from Kansas City, Missouri, at a junction with I-35 and I-70, to the Canada–US border near Pembina, North Dakota, where it connects with Manitoba ...

east of Vermillion to Maverick Junction. Named in an attempt to encourage more tourism traffic through the lands of various AmerInd tribes in southern South Dakota, it passes through or near the Yankton Sioux Indian Reservation, the

, and the Pine Ridge Indian Reservation, crossing the James River Valley, the Missouri River near Fort Randall Dam, portions of Pine Ridge, and the High Plains of South Dakota, connecting the urban areas of the middle Missouri River with the Black Hills. Portions of the road were known as the Grant Highway, Black Hills Sioux Trail, and as part of the Omaha, Rosebud and Black Hills Highway and the Custer Battlefield Trail. Towns along the road include Gregory, Winner, Olivet, Mission,

Martin Martin may refer to: Places * Martin City (disambiguation) * Martin County (disambiguation) * Martin Township (disambiguation) Antarctica * Martin Peninsula, Marie Byrd Land * Port Martin, Adelie Land * Point Martin, South Orkney Islands Austr ...

, Batesland, and Pine Ridge. Nearby towns and locales of interest include Rosebud (capital of the Rosebud Sioux Tribe), and Wounded Knee.

Legal definition

The South Dakota section of U.S. 18, other than the concurrency with

, is defined at South Dakota Codified Laws § 31-4-141.

Iowa

U.S. 18 enters

Iowa Iowa () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wiscon ...

via a Big Sioux River crossing northeast of Beloit. It overlaps U.S. Route 75 for a mile near

Hull Hull may refer to: Structures * Chassis, of an armored fighting vehicle * Fuselage, of an aircraft * Hull (botany), the outer covering of seeds * Hull (watercraft), the body or frame of a ship * Submarine hull Mathematics * Affine hull, in affi ...

and U.S. Route 59 for a mile near Sanborn. It then overlaps

U.S. Route 71 U.S. Route 71 or U.S. Highway 71 (US 71) is a major north–south United States highway that extends for over 1500 miles (2500 km) in the central United States. This original 1926 route has remained largely unchanged by encroaching Interstat ...

through Spencer. U.S. 18 passes through

Emmetsburg Emmetsburg is a city in Palo Alto County, Iowa, United States. The population was 3,706 at the time of the 2020 census. It is the county seat of Palo Alto County. Emmetsburg is located around the southern bay of Five Island Lake. History The ...

before intersecting

U.S. Route 169 U.S. Route 169 (US 169) is a north-south U.S highway that currently runs for 966 miles (1,555 km) from the city of Virginia, Minnesota to Tulsa, Oklahoma at Memorial Drive. Route description Oklahoma US 169 is a major north–south ...

at Algona. U.S. 18 then continues east through Garner before intersecting

Interstate 35 Interstate 35 (I-35) is a major Interstate Highway in the central United States. As with most primary Interstates that end in a five, it is a major cross-country, north–south route. It stretches from Laredo, Texas, near the Mexican borde ...

in Clear Lake. After a brief concurrency with I-35, U.S. 18 continues as a

freeway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms ...

bypassing Mason City to the south. At Charles City, U.S. 18 becomes a rural two-lane highway again, except for a brief concurrency with the

U.S. Route 63 U.S. Route 63 (US 63) is a , north–south United States Highway primarily in the Midwestern and Southern United States. The southern terminus of the route is at Interstate 20 (I-20) in Ruston, Louisiana; the northern terminus is at US ...

bypass of New Hampton. After passing through West Union, it turns northeast and joins U.S. Route 52 at

Postville Postville is a village in Allamakee and Clayton counties in the U.S. state of Iowa. It lies near the junction of four counties and at the intersection of U.S. Routes 18 and 52 and Iowa Highway 51, with airport facilities in the neighboring c ...

, then leaving 52 about east of Monona before crossing the

Mississippi River The Mississippi River is the List of longest rivers of the United States (by main stem), second-longest river and chief river of the second-largest Drainage system (geomorphology), drainage system in North America, second only to the Hudson B ...

into Wisconsin via the

Marquette–Joliet Bridge The Marquette–Joliet Bridge is a bridge crossing the Mississippi River, connecting Marquette, Iowa and Prairie du Chien, Wisconsin. Local residents refer to the bridge as the Prairie Bridge or the Marquette Bridge; both terms are used equally ...

in the city of Marquette. U.S. 18 is the designated route of the

Avenue of the Saints The Avenue of the Saints is a highway in the Midwestern United States that connects St. Louis, Missouri and St. Paul, Minnesota. Route description Missouri The southern end of the Avenue of the Saints is at exit 28A of Interstate 64 (I‑64) ...

between Clear Lake and Charles City.

Wisconsin

Upon entry into

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

Prairie du Chien Prairie du Chien () is a city in and the county seat of Crawford County, Wisconsin, United States. The population was 5,506 at the 2020 census. Its ZIP Code is 53821. Often referred to as Wisconsin's second oldest city, Prairie du Chien was esta ...

, US 18 is the terminus for

WIS 60 State Trunk Highway 60, often called Highway 60, STH-60 or WIS 60, is a state highway in the U.S. state of Wisconsin. It runs east–west in southern Wisconsin from Prairie du Chien on the Mississippi River at the Iowa state line to th ...

. The two routes are then concurrent until

Bridgeport Bridgeport is the most populous city and a major port in the U.S. state of Connecticut. With a population of 148,654 in 2020, it is also the fifth-most populous in New England. Located in eastern Fairfield County at the mouth of the Pequonn ...

where WIS 60 splits off to the east and US 18 crosses the

Wisconsin River The Wisconsin River is a tributary of the Mississippi River in the U.S. state of Wisconsin. At approximately 430 miles (692 km) long, it is the state's longest river. The river's name, first recorded in 1673 by Jacques Marquette as "Meskous ...

and turns east on the other side. The route joins the

US 151 U.S. Highway 151 (US 151) is a United States Numbered Highway that runs through the states of Iowa and Wisconsin. The southern terminus for US 151 is at a junction with Interstate 80 (I-80) in Iowa County, Iowa, and its northern ter ...

expressway in Dodgeville and the two remain concurrent east to

Madison Madison may refer to: People * Madison (name), a given name and a surname * James Madison (1751–1836), fourth president of the United States Place names * Madison, Wisconsin, the state capital of Wisconsin and the largest city known by this ...

(See U.S. Route 151 in Wisconsin for an interchange list). US 18 follows

US 12 U.S. Route 12 (US 12) is an east–west United States highway, running from Aberdeen, Washington, to Detroit, Michigan, for almost . The highway has mostly been superseded by Interstate 90 (I-90) and I-94, but unlike most U.S. routes that ...

south of Madison and passes through or around

Cambridge Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge bec ...

, Jefferson and Waukesha before terminating in Milwaukee at the junction of East Michigan Street and Lincoln Memorial Drive in downtown.

Major intersections

;Wyoming : in

Orin ORiN (Open Robot/Resource interface for the Network) is a standard network interface for FA (factory automation) systems. The Japan Robot Association proposed ORiN in 2002, and the ORiN Forum develops and maintains the ORiN standard. Background ...

. US 18/US 20 travel concurrently to Lusk. : in Lusk. The highways travel concurrently to the northeastern part of Niobrara County. ;South Dakota : in

. The highways travel concurrently to Oelrichs. : west of Mission. The highways travel concurrently to Mission. : southeast of

Witten Witten () is a city with almost 100,000 inhabitants in the Ennepe-Ruhr-Kreis (district) in North Rhine-Westphalia, Germany. Geography Witten is situated in the Ruhr valley, in the southern Ruhr area. Bordering municipalities * Bochum * Dortmun ...

. The highways travel concurrently to Colome. : east-southeast of Fairfax. The highways travel concurrently to south of

Armour Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or f ...

. : east of Menno : south-southwest of

. The highways travel concurrently for approximately . ;Iowa : in Lincoln Township. The highways travel concurrently through the township. : in Sanborn. The highways travel concurrently to Franklin Township. : in Spencer. The highways travel concurrently through the city. : in Algona : in Garfield Township. The highways travel concurrently to Garner. : in Clear Lake. The highways travel concurrently to Lake Township. : in Mason City : in Floyd. The highways travel concurrently to Charles City. : in New Hampton. The highways travel concurrently to Dresden Township. : in Post Township. The highways travel concurrently to Giard Township. ;Wisconsin : in Fennimore. The highways travel concurrently through the city. : east of Dodgeville. The highways travel concurrently to

. : in

. US 12/US 18 travel concurrently to

. US 14/US 18 travel concurrently through Madison. : in Madison : in Madison : northeast of Waukesha : in

Wauwatosa Wauwatosa (; known informally as Tosa; originally Wau-wau-too-sa or Hart's Mill) is a city in Milwaukee County, Wisconsin, United States. The population was 48,387 at the 2020 census. Wauwatosa is located immediately west of Milwaukee, and is a pa ...

. A southbound entrance allows access to . : Michigan Street/Lincoln Memorial Drive in

Milwaukee Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County. With a population of 577,222 at the 2020 census, Milwaukee i ...

References

External links

Endpoints of U.S. Highway 18
{{DEFAULTSORT:18 United States Numbered Highway System U.S. Highways in South Dakota U.S. Highways in Wyoming