Poles like following King Arthur's first state (6)
I believe the answer is:
kansas
'state' is the definition.
(I know that Kansas is a state)
'poles like following king arthur's first' is the wordplay.
'poles' becomes 'NS' (North and South poles).
'like' becomes 'as'.
'following' is a charade indicator (letters next to each other).
'king' becomes 'K' (abbreviation for king in chess).
'arthur's first' becomes 'a' (1st letter of 'arthur').
'ns'+'as'='nsas'
'k'+'a'='ka'
'nsas' after 'ka' is 'KANSAS'.
(Other definitions for kansas that I've seen before include "The Sunflower US state" , "''Toto, I've a feeling we're not in ... anymore'' (Dorothy in Wizard of Oz)" , "Central US state" , "US state, joined 1861" , "American state, capital Topeka" .)