While there is some debate about this, McKendree College (today McKendree University) seems to be the oldest; it is a private liberal arts college located in Lebanon, Illinois. It was founded in 1828 and originally called the Lebanon Seminary, run by the Methodist Church. The oldest public university is Illinois State University, founded in 1857 in Norman, Illinois, as a training school for teachers.
Peoria is the oldest community in Illinois. Kaskaskia and Cahokia were both founded as early as 1690(though it is possible earlier) It is for sure known that Peoria was founded before this, but it was abandoned in 1680 and was no longer a settlement..So while Peoria is thought to be older, Cahokia or Kaskaskia is known as the oldest permanent European settlement in Illinois.
Northern Illinois University was founded through the creation of a Board of Trustees for the governance of the Northern Illinois State Normal School, as part of the expansion of the normal school program established in 1857 in Normal, Illinois. In July, 1917, the Illinois Senate consolidated the boards of trustees for the five state normal schools into one state Normal School Board (Eastern Illinois State Normal School, Illinois State Normal School, Northern Illinois State Normal…
Joseph Smith's followers founded many cities and towns throughout the United States, including Nauvoo, Illinois and Salt Lake City, Utah (and most of the cities in Utah). They also founded other towns in Ohio, Missouri, Illinois, Michigan, Wisconsin, Nebraska, Utah, Idaho, Nevada, Wyoming, Arizona, California, Canada, and Mexico.