Remote odd-looking ruins around Los Angeles (7)
'remote' is the definition.
'odd-looking ruins around los angeles' is the wordplay.
'odd looking' indicates anagramming the letters.
'around' is an insertion indicator.
'los angeles' becomes 'la'.
'ruins' with letters rearranged gives 'insur'.
'insur' placed around 'la' is 'INSULAR'.
(Other definitions for insular that I've seen before include "Narrow-minded; isolated", "cut off", "Narrowly restricted in outlook or scope", "withdrawn", "Circumscribed".)