Subscription site - www.rootsireland.ie - has pages of marriages with the surname "Ellis" from 1695 to 1810. Some recorded as "Eeles"
The main concentration of the name is in County Waterford. There are a few in County Wicklow close to Bunclody. The name is found as far North as Antrim.
Surnames of Ireland by Dr. Edward MacLysaght has the following in relation to the name: Third Edition 1978
"This name, derived from an Old-English Christian name Ellis, or Elias, appears in Dublin as Elys in 1282 and occurs frequently in Irish records in every subsequent century; it has never been closely identified with any particular area and is now found mainly in Dublin and many parts of Ulster.
Nothing found in relation to the origin of Ellis Castle in County Wexford.