Historical clue formulations

• County in New Mexico or Colorado — 2017-12-31
• County in Colorado or New Mexico — 2016-08-09
• County whose seat is La Junta — 2013-08-17
• New Mexico county — 2012-02-16
• County NE of El Paso — 2011-12-03
• New Mexico county — 2011-09-11
• New Mexico county whose seat is Alamogordo — 2010-11-22
• Alamogordo's county — 2010-09-16
• New Mexico county — 2009-03-11
• Alamogordo's county — 2007-04-11
• New Mexico county — 2006-10-25
• County with the White Sands National Monument — 2006-10-22
• New Mexico county — 2006-08-27
• Alamogordo's county — 2006-04-06
• New Mexico county where the first atomic bomb was exploded — 2000-04-15
• Alamogordo's county — 1999-09-15
• Alamogordo's county — 1999-04-10
• New Mexico county — 1996-06-07
• New Mexico county — 1994-11-05
• Alamogordo's county — 1993-12-10