Beast roaming two thirds of Oregon (4)
I believe the answer is:
ogre
'beast' is the definition.
(I've seen this in another clue)
'roaming two thirds of oregon' is the wordplay.
I cannot quite see how this works, but
'of' could be 'o' and 'o' is located in the answer.
The remaining letters 'gre' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ogre that I've seen before include "Wicked and inhuman person" , "Ugly giant" , "Monster, troll" , "One to gobble flesh" , "Giant of folklore who liked to eat humans" .)