Illinois Unit By mzam23 Jun 23, 1671 Jacques Marquette and Louis Jolliet explore Illinois Period: Jan 1, 1673 to Jun 19, 2012 Illinois Jun 23, 1763 Great Britain gains control of Illinois Jun 23, 1779 Chicago is established Jun 23, 1818 Illinois becomes 21st state Jun 23, 1860 Illinois resident Abe Lincoln is elected president Jun 23, 1871 The Great Chicago Fire destroys most of the city Jun 23, 1974 The Sears Tower is finished Jun 23, 1980 Ronald Regan from Illinois is elected president Jun 23, 1993 Mississippi river floods millions of acres of Illinois farmland Jun 23, 2008 Illinois resident Barack Obama is elected president
