U.S. Route 31 (US 31) is a part of the

United States Numbered Highway System 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 h ...

that runs from

Spanish Fort, Alabama Spanish Fort is a city in Baldwin County, Alabama, United States, located on the eastern shore of Mobile Bay. The 2020 census lists the population of the city as 10,049. It is a suburb of Mobile and is part of the Daphne-Fairhope-Foley metro ...

, to

Mackinaw City, Michigan Mackinaw City ( ) is a village in Emmet and Cheboygan counties in the U.S. state of Michigan. The population was 846 at the 2010 census, the population increases during summertime, including an influx of tourists and seasonal workers who serve ...

. It enters the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sove ...

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th ...

via the

George Rogers Clark Memorial Bridge The George Rogers Clark Memorial Bridge, known locally as the Second Street Bridge, is a four-lane cantilevered truss bridge crossing the Ohio River between Louisville, Kentucky and Jeffersonville, Indiana, that carries US 31. History Debate ...

between

Louisville, Kentucky Louisville ( , , ) is the largest city in the Commonwealth of Kentucky and the 28th most-populous city in the United States. Louisville is the historical seat and, since 2003, the nominal seat of Jefferson County, on the Indiana border ...

, and

Clarksville, Indiana Clarksville is a town in Clark County, Indiana, United States, along the Ohio River and is a part of the Louisville Metropolitan area. The population was 22,333 at the 2020 census. The town was founded in 1783 by early resident George Rogers Cla ...

. The of US 31 that lie within Indiana serve as a major conduit. Some of the highway is listed on the National Highway System. Various sections are rural two-lane highway and urbanized four- or six-lane divided expressway. The northernmost community along the highway is

South Bend South Bend is a city in and the county seat of St. Joseph County, Indiana, on the St. Joseph River near its southernmost bend, from which it derives its name. As of the 2020 census, the city had a total of 103,453 residents and is the fourt ...

near the

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 ...

state line. US 31 was first designated as a US Highway in October 1926. A northern section (from Rochester to South Bend) and a far southern section (on old US 31W into Louisville on the K&I Bridge) of the highway originally served as part of the

Dixie Highway Dixie Highway was a United States auto trail first planned in 1914 to connect the Midwest with the South. It was part of a system and was expanded from an earlier Miami to Montreal highway. The final system is better understood as a network of ...

. US 31 was the Jackson Highway from Indianapolis to Seymour. US 31 replaced the original State Road 1 (SR 1) designation of the highway which dated back to the formation of the Indiana State Road system. SR 1 ran from Clarksville through

Indianapolis Indianapolis (), colloquially known as Indy, is the state capital and most populous city of the U.S. state of Indiana and the seat of Marion County. According to the U.S. Census Bureau, the consolidated population of Indianapolis and Marion ...

to South Bend and ended at the Michigan state line.

Route description

Only the segment of US 31 that is north of Indianapolis is included as a part of the National Highway System (NHS). The NHS is a network of highways that are identified as being most important for the economy, mobility and defense of the nation. The highway is maintained by the

Indiana Department of Transportation The Indiana Department of Transportation (INDOT) is a governmental agency of the U.S. state of Indiana charged with maintaining and regulating transportation and transportation related infrastructure such as state owned airports, state highways a ...

(INDOT) like all other U.S. Routes in the state. The department tracks the traffic volumes along all state highways as a part of its maintenance responsibilities using a metric called

average annual daily traffic Annual average daily traffic, abbreviated AADT, is a measure used primarily in transportation planning, transportation engineering and retail location selection. Traditionally, it is the total volume of vehicle traffic of a highway or road for a ...

(AADT). This measurement is a calculation of the traffic level along a segment of roadway for any average day of the year. In 2010, INDOT figured that lowest traffic levels were the 3,690 personal vehicles and 160 commercial vehicles that used the highway daily near

Memphis Memphis most commonly refers to: * Memphis, Egypt, a former capital of ancient Egypt * Memphis, Tennessee, a major American city Memphis may also refer to: Places United States * Memphis, Alabama * Memphis, Florida * Memphis, Indiana * Memp ...

. The peak traffic volume was 168,770 personal vehicles and 18,090 commercial vehicles along the section of US 31 concurrent with

Interstate 465 Interstate 465 (I-465), also known as the USS ''Indianapolis'' Memorial Highway, is the beltway circling Indianapolis, Indiana, United States. It is roughly rectangular in shape and has a perimeter of approximately . It lies almost complet ...

(I–465).

Jeffersonville to Columbus

US 31 overlaps I-65 in Jeffersonville, after crossing the

from Kentucky. It then diverges as the access frontage lanes before splitting off north of Jeffersonville at Clarksville and proceeding to

. US 31 was widened to two lanes in both directions for its length through Columbus in the early 2000s.

Columbus to Indianapolis

At I-465 on the south side of Indianapolis, US 31 is routed onto I-465 on the east side of the city. This is the closest approach the highway makes to downtown Indianapolis. Previously the northbound route of the highway through Indianapolis was on East Street, Madison Avenue, Delaware Street, North Street, and onto Meridian Street; southbound was on Meridian Street, North Street, Pennsylvania Street, Madison Avenue, and onto East Street.

Indianapolis to Michigan

US 31 exits I-465 (coincidentally at exit 31) in Carmel, and continues northward 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 ...

through Westfield. North of SR 38, it reverts to a

divided highway A dual carriageway ( BE) or divided highway ( AE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are ...

until reaching the Kokomo area, where it again becomes a full freeway to bypass that city to the east. North of the Kokomo area US 31 again becomes a rural divided highway, which skirts

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...

Rochester Rochester may refer to: Places Australia * Rochester, Victoria Canada * Rochester, Alberta United Kingdom *Rochester, Kent ** City of Rochester-upon-Medway (1982–1998), district council area ** History of Rochester, Kent ** HM Prison ...

, and

Plymouth Plymouth () is a port city status in the United Kingdom, city and unitary authority in South West England. It is located on the south coast of Devon, approximately south-west of Exeter and south-west of London. It is bordered by Cornwall to ...

. At US 30 east of Plymouth, US 31 becomes a freeway again and remains so for the rest of its journey in the state. After bypassing

Lakeville Lakeville may refer to: Canada *Wilmot Parish, New Brunswick#Lakeville, Lakeville, a local service district north of Woodstock, New Brunswick **Lakeville, Carleton County, New Brunswick, a community within the local service district *Lakeville, Wes ...

to the east, US 31 approaches

. There the route converges with US 20 (

St. Joseph Valley Parkway The St. Joseph Valley Parkway is a freeway in the U.S. states of Indiana and Michigan, serving as a bypass route around Elkhart, Mishawaka, and South Bend in Indiana and Niles in Michigan. The freeway runs to the south and west of Elkhart an ...

) and proceeds west and then north to bypass South Bend. After US 20 splits off to the west near the South Bend Airport, US 31 has an interchange with the

Indiana Toll Road The Indiana Toll Road, officially the Indiana East–West Toll Road, is a tolled freeway that runs for east–west across northern Indiana from the Illinois state line to the Ohio state line. It has been advertised as the "Main Street of the ...

(

I-80 Interstate 80 (I-80) is an east–west transcontinental freeway that crosses the United States from downtown San Francisco, California, to Teaneck, New Jersey, in the New York metropolitan area. The highway was designated in 1956 as one o ...

I-90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain West, Great Plains, Midwest, an ...

) before proceeding north into

History

US 31 was signed into law by the Governor on March 7, 1917, as Main Market Highway 1, and signs were installed on June 1 of that year. The name was changed to State Road 1 within a year when Indiana began the state road system. By 1924, most of the route was paved, leaving only from Columbus to Franklin and from Peru to Plymouth that was unpaved. On October 1, 1926, US 31 was designated along what was SR 1 at the time. In the late 2000s, INDOT began a process of converting US 31 to

Interstate Highway standards Standards for Interstate Highways in the United States are defined by the American Association of State Highway and Transportation Officials (AASHTO) in the publication ''A Policy on Design Standards: Interstate System''. For a certain highway to ...

from

. Three projects were completed in the early 2010s: an upgrade of the road from

I-465 Interstate 465 (I-465), also known as the USS ''Indianapolis'' Memorial Highway, is the beltway circling Indianapolis, Indiana, United States. It is roughly rectangular in shape and has a perimeter of approximately . It lies almost compl ...

in Indianapolis to SR 38 north of Westfield, a new freeway bypass of Kokomo, and a new freeway segment from

to South Bend, which was constructed largely on a new alignment. A portion of the Plymouth–South Bend section was dedicated as the Richard W. Mangus Memorial Highway, in honor of the local

state representative A state legislature is a legislative branch or body of a political subdivision in a federal system. Two federations literally use the term "state legislature": * The legislative branches of each of the fifty state governments of the United S ...

who supported the freeway's construction, at the ribbon-cutting ceremony on August 27. The entirety of the former segment of US 31 bypassed by the freeway segment in Kokomo and a portion of the one bypassed between Plymouth and South Bend were designated as SR 931.

Future

The remaining of US 31 between South Bend and Indianapolis is gradually being converted to a

limited access highway A limited-access road, known by various terms worldwide, including limited-access highway, dual-carriageway, expressway, limited access freeway, and partial controlled access highway, is a highway or arterial road for high-speed traffic which ...

without traffic signals, starting with an interchange at SR 28 in Tipton County which opened in November 2016. As of 2018, there were six traffic signals left between Indianapolis and South Bend, and a program introduced by Governor Eric Holcomb in September 2018 proposed to remove four of those. All six signals are expected to be removed by 2026. The approximately stretch of US 31 between SR 38 in Hamilton County and SR 931 in Tipton County, south of Kokomo, was planned to be converted to

, with estimated completion in 2025. However, after the state determined that the original plans would severely limit access within Tipton County, those upgrades were removed from consideration until further study could be completed and these issues mitigated. Current upgrade plans are only slated for Hamilton County.

Major intersections

Supplemental routes

References

External links