Eastern lake found in the West - that's strange (5)
I believe the answer is:
eerie
'strange' is the definition.
(eerie means odd or strange)
'eastern lake' is the wordplay.
'eastern' becomes 'e'.
'lake' becomes 'erie' (Lake Erie is one of the Canadian/US 'Great Lakes').
'e'+'erie'='EERIE'
'found in the west that's' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for eerie that I've seen before include "Spectral" , "Spooky, macabre" , "Spooky, unearthly" , "Uncannily strange" , "Frighteningly odd" .)