Illinois is a US state situated in the country's Midwestern region where it occupies an area of 57,914 square miles. Human communities have lived within the borders of Illinois for a long time, and some of the most important events that shaped Illinois' borders occurred after the arrival of the Europeans into the region. In the modern era, Illinois shares its borders with six states including Iowa, Michigan, Kentucky, Missouri, Indiana, and Wisconsin.
Border with Iowa
Illinois and Iowa are separated by a border located in the state's western section. The Mississippi River forms much of the boundary between the two states. Several Illinois counties are situated along the borders with Iowa such as Rock Island, Whiteside, and Carroll. On the Iowa side of the border, some of the counties situated along the border include Jackson, Dubuque, and Scott. There are several important cities located along the border between the two states such as Davenport, Moline, and Bettendorf that form part of the Quad Cities. Other cities that form part of the Quad Cities include East Moline and Rock Island. Davenport is one of Iowa's most important cities as it is the seat of Scott County. The city is also the largest among the Quad Cities and the third largest in the state. The most important Quad City on the Illinois side of the border is Rock Island which is the seat of Rock Island County. In 2015, the city was ranked among the best small cities in the US.
Border with Indiana
Indiana borders Illinois on its eastern edge. A section of the border between the two states is located within Lake Michigan. Another section of the border between the two states traces the path of the Wabash River. One of the most well-known sites along the border is a monument which is known as the Illinois-Indiana Boundary Monument. The monument is situated close to a former power plant, and it marks the border between the two states. The monument is considered to be one of Chicago's oldest as it was put up in 1833.
Border with Michigan
The boundary that separates Michigan and Illinois is situated in the northeastern section of the state. The entire border between the two states is located within Lake Michigan. During the 19th century, it had been proposed that the border between Illinois and Michigan be situated to the south of Lake Michigan. The initial position of the border would have significantly reduced Illinois' territory and denied it a shoreline along Lake Michigan. The position of the border was shifted because of lobbying by Nathaniel Pope and his brother. At the time, Nathaniel Pope was the congressional delegate for Illinois Territory while his brother was a senator representing Kentucky. The position of the border was shifted to allow the Great Lakes shipping route to be connected to the Mississippi River and the Illinois River. Linking the Great Lakes to the two rivers was important during the civil war as it provided a route to transport supplies and troops during the civil war. Shifting the position of the border was beneficial to Illinois as the state gained more than 5 million acres of fertile farmland and shoreline along the lake. A shipping port was later established in the territory that Illinois had acquired that later developed into the city of Chicago. In the modern era, Chicago is one of the most important cities in the US. In 2017 Chicago was ranked as the city with the highest population in the Midwestern section of the US.
Border with Missouri
Missouri borders Illinois on its southwestern edge. The border between the two states primarily traces the path of the Mississippi River. There are several towns located on the Illinois side of the border such as Quincy and Alton. Some of the towns located on the Missouri side of the border include Saint Louis and Festus. Quincy is one of the most important cities in Illinois as it is the seat of Adams County. The city covers an area of roughly 16 square miles, and in 2016 it was home to roughly 38,531 people.
Border with Kentucky
Kentucky and Illinois are separated by a boundary situated in the southeastern section of Illinois. The border between the two states primarily traces the path of the Ohio River. In 1792, Kentucky's border with Illinois was declared to be the low-water mark of the Ohio River's northern edge. During the 20th century, according to an article in the New York Times, Illinois and Kentucky were involved in a dispute about the location of the border. The dispute was caused by a shift in the position of the low-water mark. The Supreme Court appointed a retired judge to listen to petitions from lawyers representing the two states. The Kentucky lawyers believed that Kentucky's border should be situated on the northern bank of the Ohio River. On the other hand, Illinois' lawyers believed that the state's border with Kentucky was situated approximately 100 feet from the shore. The issue was extremely important to both states as it affected the granting of fishing licenses. In 1991, the Supreme Court declared that the Illinois lawyers were right and granted the state control over part of the Ohio River.
Border with Wisconsin
Wisconsin borders Illinois on its northern edge. Several major towns are located on the Illinois side of the border such as Rockford and Freeport. Some of the important towns located on the Wisconsin side of the border include Janesville, Platteville, and Beloit. Rockford is one of the major cities in Illinois as it is the seat of Winnebago County. Despite being the seat of Winnebago County, part of the county is located in Ogle County. Janesville is one of the major cities in Wisconsin as it is the seat of Rock County as well as the county's largest city.
The Economy of Illinois
Illinois has the 5th largest economy in terms of GDP in the whole country and has a diversified economy, having some of the country’s largest companies in the metropolitan area of Chicago. Some of the largest organization includes Boeing, Allstate, Heinz, Kraft, Caterpillar, McDonald’s, Walgreens, United Airlines, and Motorola among others. The city of Chicago hosts the headquarters of Chicago Mercantile Exchange, which is the largest futures exchange in the world. In 2018, Chicago had a GDP of $857 billion, making the state the 5th highest in the nation.