Missouri and Ohio (6)
I believe the answer is:
rivers
'missouri and ohio' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rivers that I've seen before include "Comedienne Joan" , "Large natural streams of water" , "''Only Our ... Run Free'' (McConnell ballad)" , "Thames and Hudson?" , "''Only Our ... Run Free'' (MacConnell ballad)" .)