1000 lines welcoming Queen in Irish county (5)
I believe the answer is:
kerry
'irish county' is the definition.
(I've seen this before)
'1000 lines welcoming queen' is the wordplay.
'k000' becomes 'k' (synonyms).
'lines' becomes 'ry' (abbreviation for railway).
'welcoming' is an insertion indicator (in sense of 'inviting in').
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'k'+'ry'='kry'
'kry' enclosing 'er' is 'KERRY'.
'in' is the link.
(Other definitions for kerry that I've seen before include "County < girl" , "County of Ireland" , "Irish county" , "County of Tralee" .)