"Cleared" mens that you have killed all enemies there lets say camp skyrim has 5-7 bandits and mayby a leader. You need to kill them all once to get that camp "Cleared".
Witchmist Grove is propably part of some quest, since there is that weirdo granny Moira wich standin infront of her house. She will not attack if u dont attack so very likely a quest place.
There are some other places that will not be marked as "Cleared" such as towns (example riverwood), or farms, cities, stone things (13 of them; warrior, mage, thief, lover, serpent etc) and some random good to see-places. I dont remember if military camps can be "Cleared".
:spotted owl: :spotted owl: