Historical clue formulations

• Tributary of the Mississippi — 2017-09-15
• Mississippi feeder — 2016-07-01
• Mississippi's ___ River — 2013-05-21
• ___ City, Miss. — 2013-04-07
• Mississippi river named by La Salle — 2009-11-07
• ___ City, Miss. — 2003-04-27
• Mississippi feeder — 1999-05-28
• Mississippi tributary — 1995-02-21
• Mississippi waterway — 1994-09-01