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Current on line telephone book for Limerick has 21 Costelloe and 43 Costello
Current on line telephone book for Tipperary has 7 Costelloe and 47 Costello's 8 in Nenagh.
The Tithe Applotments are now on line 1823-1837
www.genealogy.nationalarchives.ieGriffith Valuation: 1850's
www.askaboutireland.ie1901/1911 Census,
www.census.nationalarchives.ieAnnette Code