Historical clue formulations

• Guam or the U.S. Virgin Islands: Abbr. — 2021-05-02
• Alaska, before 1959: Abbr. — 2018-12-19
• Apt. amenity, perhaps — 2017-05-12
• Okla. or Dak., once — 2015-05-26
• Guam, e.g.: Abbr. — 2013-11-03
• The U.S. Virgin Is., e.g. — 2013-07-02
• Okla., until 1907 — 2013-05-22
• La., e.g., once — 2011-06-25
• Louisiana ___: Abbr. — 2011-04-08
• Colonial land: Abbr. — 2011-04-03
• Guam or the U.S. Virgin Isls. — 2011-01-17
• Abbr. on an old map of the West — 2010-12-23
• Yukon, e.g.: Abbr. — 2010-08-22
• La., e.g., from 1805 to 1812 — 2010-06-02
• The Dakotas, once: Abbr. — 2009-11-05
• U.S. Virgin Is., e.g. — 2009-02-17
• Abbr. on maps of the Old West — 2009-02-15
• Nonmember of a union: Abbr. — 2009-01-18
• The U.S. Virgin Is., e.g. — 2009-01-06
• Apt. amenity — 2008-10-25
• Union member of the future: Abbr. — 2008-10-24
• Ariz., e.g., before 1912 — 2008-05-19
• Dakota ___ (old geog. designation) — 2007-11-26
• Australia's Northern ___: Abbr. — 2007-08-05
• Oreg. or La., once — 2007-02-21
• Abbr. on old U.S. maps — 2006-07-01
• Hawaii, before 1959: Abbr. — 2006-04-12
• The Virgin Is., e.g. — 2005-01-05
• Hawaii, once: Abbr. — 2003-12-18
• Virgin Is., e.g. — 2003-07-08
• Virgin Is., e.g. — 2003-04-08
• Okla., before 1907 — 2002-11-22
• Status before statehood: Abbr. — 2002-05-14
• Guam, e.g.: Abbr. — 2001-10-15
• Yukon, e.g.: Abbr. — 2001-08-02
• Virgin Isls., e.g. — 2000-11-22
• Dakotas, once: Abbr. — 2000-09-18
• Virgin Islands, e.g.: Abbr. — 1998-12-09
• Dak., once — 1998-06-10
• Pre-1821 Missouri, e.g.: Abbr. — 1997-03-11
• Alas., once — 1997-02-02
• Map abbr. — 1995-09-24