lol - part of the problem is that castles don't generally have names ... they are the "Castle of Xxx" or the "Xxx Castle" (at least if using English)
Castles and fortified locations are more interesting because they influence other names ...
In Ireland or Scotland, any place-name starting with "Dun" or "Rath" implies that there is or was a fortified village or town (generally dates back BEFORE the creation of Norman-esque "Castles" - the Gaelic term for a Norman castle is "caisleán" (Irish) or "caisteal" (Scots Gaelic))