Poles like following King Arthur's first state (6)
I believe the answer is:
kansas
'state' is the definition.
(Kansas is an example)
'poles like following king arthur's first' is the wordplay.
'poles' becomes 'NS' (North and South poles).
'like' becomes 'as'.
'following' means one lot of letters go next to another.
'king' becomes 'K' (abbreviation for king in chess).
'arthur's first' becomes 'a' (1st letter of 'arthur').
'ns'+'as'='nsas'
'k'+'a'='ka'
'nsas' put 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" .)