Dunlap, Dunlop
Dunlap, Dunlop—These two Scottish names are anglicised forms of McDunlevy (Mac Duinnshléibhe), whose ancestors went to Scotland from eastern Ulster some 600 years ago. Delap is a more modern anglicisation. In Donegal and Derry, the O'Lappins (O'Lapáin) have assumed the name of Dunlap.
Alphabetical Index of Anglicised Surnames in Ireland
See also Woulfe’s Irish Names and Surnames
… and O'Hart's Irish Pedigrees