Lake Michigan
Illinois is bordered by Lake Michigan to the northeast.
In most cases the eastern boundary of something will touch the western boundary of the next door something. Where "something" can be a state, province, country, estate, ocean, lake river, Earth plate etc.
Lake Michigan separates the state of Wisconsin from the states of Illinois and Indiana. Additionally, it borders the southern part of Michigan's Lower Peninsula. The lake serves as a natural boundary and is an important geographical feature for these states.
No, it does not cross the border of Maine. The eastern most part of Lake Winnipesaukee is approximately 25 miles from the Maine border.
The boundary between Illinois and Missouri is primarily a political boundary, defined by the Mississippi River. This river serves as a natural border for much of the state line, particularly in the eastern part. Additionally, the boundary follows specific survey lines established in early statehood, making it a combination of natural and political delineations.
There are three lakes that form part of the northeatern boundary of South Dakota. They are Mud Lake, Lake Traverse, and Big Stone Lake.
Indiana and Illinois
Illinois
Illinois is located in the Midwest Region of the United States.
Wisconsin is bordered by four states: Minnesota to the west, Iowa to the southwest, Illinois to the south, and Michigan to the north and east, with Lake Michigan forming part of its boundary.
Canada and the United States