Illinois Route 142 is a major arterial road in southeastern Illinois

Illinois

Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

. It runs from near the town center of Equality

Equality, Illinois

Equality is a village in Gallatin County, Illinois, United States. The population was 721 at the 2000 census. Near the village are two points of interest, the Crenshaw House and the Garden of the Gods Wilderness.-History:...

 at Calhoun Street, a local road, north to Illinois Route 37

Illinois Route 37

Illinois Route 37, or Illinois 37, is a north–south route in southern Illinois. It is in length. Originally connecting Effingham to Cairo, it was a heavily-traveled highway before Interstate 57 was opened. That Interstate, which lies very close to most of Illinois 37 , supplanted it as a...

 and the northern terminus of Illinois Route 148

Illinois Route 148

Illinois Route 148 is a north–south state road in southern Illinois. It runs from Illinois Route 37 at Pulleys Mill north to the western terminus of Illinois Route 142 and Illinois 37 south of downtown Mount Vernon...

 in Mount Vernon

Mount Vernon, Illinois

Mount Vernon is a city located near the center of Jefferson County, Illinois, in the United States. In the 2010 census, the city's reported population was 15,277 people....

. This is a distance of 55.06 miles (88.61 km).

Route description

Illinois 142 runs northwest from Equality. Before reaching Eldorado

Eldorado, Illinois

Eldorado is a city in Saline County, Illinois, United States. The population was 4,122 at the 2010 census, with a 1925 peak of 8,000. Although the city's name is spelled as if it were Spanish, the name was originally "Elder-Reado" -- a combination of the last names of the town's two founders,...

, it intersects Illinois Route 13

Illinois Route 13

Illinois Route 13 is a major east–west state route in southern Illinois. Illinois 13 has its western terminus at Centreville at Illinois Route 157 and its eastern terminus at the Kentucky state line and the Ohio River, at Kentucky Route 56. This is a distance of .- Route description :Illinois...

 and U.S. Route 45

U.S. Route 45

U.S. Route 45 is a north–south United States highway. US 45 is a border-to-border route, from Lake Superior to the Gulf of Mexico. A sign at the highway's northern terminus notes the total distance as ....

. Illinois 142 largely parallels the North Fork of the Saline River

Saline River (Illinois)

The Saline River is a tributary of the Ohio River, approximately long, in the Southern Illinois region of the U.S. state of Illinois. The river drains a large section of southeast Illinois, with a drainage basin of . The major tributaries include the South Fork, Middle Fork and North Fork, all...

 before reaching McLeansboro

McLeansboro, Illinois

McLeansboro is a city in Hamilton County, Illinois, United States. The population was 2,883 at the 2010 census. It is the county seat of Hamilton County. Located in Southern Illinois, the town was named for Dr. William B. McLean, who donated the land for its founding...

 and intersecting Illinois Route 14

Illinois Route 14

Illinois Route 14 is a major east–west highway in southern Illinois. It runs from U.S. Route 51 south of Du Quoin to the New Harmony Toll Bridge over the Wabash River to State Road 66 at the Indiana state line...

 and Illinois Route 242

Illinois Route 242

Illinois Route 242 is a north–south state highway in southern Illinois that runs from Illinois Route 142 in McLeansboro north to Illinois Route 15 in Wayne City. The route serves as a spur of Illinois Route 142, which runs north–south from Mount Vernon to Equality. Route 242 also...

, a spur of Illinois 142. Route 142 then crosses Interstate 64

Interstate 64

Interstate 64 is an Interstate Highway in the Midwestern and Southeastern United States. Its western terminus is at I-70, U.S. 40, and U.S. 61 in Wentzville, Missouri. Its eastern terminus is at an interchange with I-264 and I-664 at Bowers Hill in Chesapeake, Virginia. As I-64 is concurrent with...

 without an interchange before entering the Mount Vernon area.

History

SBI Route 142 ran from Effingham

Effingham, Illinois

Effingham is a city in Effingham County, Illinois, United States. The population was 12,384 at the 2000 census. It is the county seat of Effingham County....

 to McLeansboro along what is Illinois 37 today. It was changed in the mid 1930s to its current routing. In 1947, U.S. Route 460

U.S. Route 460

U.S. Route 460 is a spur of U.S. Route 60. It currently runs for 655 miles from Norfolk, Virginia at U.S. Route 60 at Ocean View to Frankfort, Kentucky at U.S. Route 60. It passes through the states of Virginia, West Virginia, and Kentucky...

was applied onto Illinois 142 from Mount Vernon to McLeansboro; Illinois 142 was then moved onto what was then Illinois Route 147

Illinois Route 147

Illinois Route 147 is an east–west state road in southern Illinois. It runs from Illinois Route 146 east of Vienna to Illinois Route 145 in Glendale. This is a distance of .- Route description :...

, which had been Illinois Route 142A, or the highway north from McLeansboro to Wayne City

Wayne City, Illinois

Wayne City is a village in Wayne County, Illinois, United States. The population was 1,089 at the 2000 census.-Geography:Wayne City is located at ....

.

This configuration lasted until 1974, when U.S. 460 was decommissioned and the current routing for Illinois 142 re-established from Mount Vernon to McLeansboro. The road from McLeansboro north to Wayne City was again renamed, to Illinois 242.