Yes it is.
Illinois was admitted into the Union in 1818.
Yes, Illinois is in the United States of America on the continent of North America.
As a part of Illinois it became a part of the US on 3 December 1818.
It is a city within the US State of Illinois.
The same year as the rest of Illinois, in 1818.
Illinois is located in the Midwest Region of the United States.
Illinois is located in the Midwest Region of the United States.
Chicago is located in Illinois.
All of these are states in the US.
Illinois was admitted to the Union on December 3, 1818 becoming the 21st state to join the union.
Chicago is part of Cook County which is part of the State of Illinois which is part of the United States of America. So, Chicago isn't far from the US because it is IN the US.
In the US Supreme Court it was reversed in part and affirmed in part. For decision see below:
The US did not buy Illinois specifically from the French before or after the Louisiana Purchase. Illinois was part of the larger territory acquired by the US through the Louisiana Purchase in 1803. The Louisiana Purchase included the entire Mississippi River Basin, which encompassed present-day Illinois.
Illinois is located in the Midwest Region of the United States. Illinois is bordered by Wisconsin to the north, Iowa to the northwest, Missouri to the west, Kentucky to the southeast, and Indiana to the east. Illinois is bordered by Lake Michigan to the northeast.