"Mulderry" is one of a number of modern surnames deriving from the ancient Irish Už Maoldoraidh clan. The Už Maoldoraidh originated in Donegal, north-western Ireland in the 9th century AD and until the late 12th century were a dominant clan in the region, occasionally laying claim to "kingship of all Ireland".
Today, there are perhaps 200 individuals worldwide bearing the name "Mulderry". They can be found in Ireland, Britain, USA, Australia, New Zealand and, allegedly, Argentina. The greatest concentration is now in the north-eastern USA, centered on Albany, New York.
A Coat of Arms has been granted to Louis Mulderry who has written a short history of the family.