Illinois Route 1 (IL 1) is a state highway in the U.S. state of Illinois. Running parallel to the Indiana border, the highway starts at the free ferry crossing to Kentucky at Cave-in-Rock on the Ohio River and runs north to the south side of Chicago as Halsted Street at an intersection with Interstate 57. This is a distance of .
thumb|left|IL 1 and IL 14
Continuing northeast for , the route reaches the city of Carmi. In Carmi, IL 1 is known as West Main Street, paralleling nearby IL 14. At the junction of Oak Street and West Main Street, IL 1 and IL 14 run concurrently. IL 1 and IL 14 follow East Main Street out of downtown Carmi, changing names to Cross Street as it enters the village of Crossville. In Crossville, IL 1 and IL 14 split, with the latter turning east on East Main Street. IL 1 continues north on North Cross Street through Crossville before leaving the village. Returning to its northeast progression, the route passes the community of Calvin before reaching a junction with Interstate 64 (I-64, exit 130). The interchange marks the entrance to the village of Grayville. In Grayville, the route crosses the Edwards County line and reaches a junction with the southern end of IL 130 (Hagedom Road).
History
The northern portion of the Vincennes Trace or Vincennes Trail, an Indian trail which ran some to Vincennes, Indiana, was called Hubbard's Trace or Hubbard's Trail since it connected Fort Dearborn in Chicago with Gurdon Saltonstall Hubbard's more southerly trading outposts. It took on the name State Road after some state-funded improvements. Vincennes Avenue, one of Chicago's rare diagonal streets, is a vestige of the Vincennes Trace, and further south the trail eventually became IL 1. In its early days, State Road was unpaved and known for having mud so deep it was jokingly said that it could suck down a horse and buggy.
The Hubbard Trace was a wagon trail laid out by Gurdon Saltonstall Hubbard after he opened a trading post in Danville in 1828, located east of a former Kickapoo village. The trail went north through Hoopeston (Chicago Road) to Watseka, named after Hubbard's Potawatomi wife Watch–e–kee. From there the trail led to Hubbard and Noel La Vasseur's fur warehouse and trading post in Momence, named for Potawatomi chief Momenza. It then went north to Beecher and Blue Island, eventually becoming Vincennes Avenue and State Street to Fort Dearborn south of the Chicago River.
IL 1 was commissioned in 1918 as SBI Route 1. The original route had extended further along the northern end into Chicago along Vincennes Avenue and Michigan Avenue, and on the southern end from Norris City to Metropolis.
When US 45 was established from Norris City to Metropolis, IL 1 shifted east to Cave-In-Rock, replacing a part of Illinois Route 140 in the process. Kentucky Route 91 continues across the Ohio River.
In 1937, IL 1 was shifted southeast away from Albion to directly connect Mount Carmel and Grayville. Eventually, IL 15 and IL 130 replaced IL 1 to Albion.
In the 1950s, a freeway, then known as the Calumet Expressway, was constructed south from Chicago. This was designated IL 1, while the old highway along Halsted Street was signed Alternate IL 1 (Alt. IL 1). By 1964, IL 1 was restored to its old alignment, and IL 394 was applied to the expressway south of the portion designated as I-94 (the I-94 portion now being known as the Bishop Ford Freeway). At this time, IL 1 was discontinued north of I-57.
Dixie Highway
Most of IL 1 north of Danville was part of the western division of the Dixie Highway, which goes through downstate Illinois and enters the Chicago area as it passes through Beecher. From here it follows the Vincennes Trail north and splits into the Bishop Ford Freeway (formerly the Calumet Expressway) and Chicago Road (one of the original roads into Chicago from the south). The Dixie Highway follows Chicago Road through Crete (where it is known as Main Street), Steger and South Chicago Heights (where it shares a junction with Sauk Trail).
As IL 1 continues north, it has a junction with Lincoln Highway (US 30) in Chicago Heights. This is sometimes known as the "Crossroads of the Nation", because it is the intersection of two major auto trails. This intersection helped cities such as Chicago Heights thrive in its early days. Approximately two blocks after this intersection, Dixie Highway splits from Chicago Road and continues north through Flossmoor and Homewood. At the north end of Homewood's downtown, the road turns and goes under the Illinois Central Railroad tracks, which now carries both the Metra Electric Line and Amtrak trains. The road continues north through East Hazel Crest and past the Markham Rail Yards and under the Tri-State Tollway.
Past the tollway, the road enters Hazel Crest, Markham and then Harvey. As the road continues, creating a border between the towns of Dixmoor and Posen, its name changes to Western Avenue.
When the road enters Blue Island, it splits into two streets, (Western and Gregory), and realigns itself into one when it reaches Burr Oak Avenue. The road then enters the city of Chicago. Through Chicago, Western Avenue is a major boulevard, which continues north through the city to the town of Evanston (where it is named Asbury Street), which is where the Dixie Highway ends.