Madness about to be cut short in Canadian province (8)
I believe the answer is:
manitoba
'canadian province' is the definition.
(Manitoba is an example)
'madness about to be cut short' is the wordplay.
'madness' becomes 'mania' (I've seen this in another clue).
'about' indicates putting letters inside.
'cut short' means to remove the last letter.
'to'+'be'='tobe'
'tobe' with its last letter removed is 'tob'.
'mania' placed around 'tob' is 'MANITOBA'.
'in' acts as a link.
(Other definitions for manitoba that I've seen before include "Winnipeg area" , "Is Oman a bit in Canada, strangely?" , "northern territory" , "Canadian prairie province" , "place in the prairies" .)