Historical clue formulations

• Illinois home of the John Deere Pavilion — 2013-02-08
• Illinois home of Black Hawk College — 2011-01-16
• One of the Quad Cities, in Illinois — 2007-05-22
• Illinois city — 2006-05-02
• John Deere headquarters city — 2000-01-22
• Illinois city — 1995-04-16