Historical clue formulations

• Big Ten school: Abbr. — 2018-08-29
• Neighbor of Colo. — 2015-04-01
• State for which a Springsteen album is named: Abbr. — 2012-05-13
• Wyo. neighbor — 2012-05-06
• Lincoln's state: Abbr. — 2009-03-10
• Hastings, ___, where Kool-Aid was invented: Abbr. — 2009-02-08
• Lincoln's home: Abbr. — 2005-08-18
• Neighbor of Colo. — 2004-05-23
• North Platte locale: Abbr. — 2001-05-24
• Wyo. neighbor — 2001-04-03
• I-80 runs through it — 2000-01-09
• 1867 admission to the Union: Abbr. — 1999-10-09
• Colo. neighbor — 1997-05-04