Show ContentsDempser History, Family Crest & Coats of Arms

Today's Irish surnames are underpinned by a multitude of rich histories. The name Dempser originally appeared in Gaelic as Ó Diomasaigh, from the word "diomasach," which means "proud." 1

Early Origins of the Dempser family

The surname Dempser was first found in King's County and Queen's County, where they were traditional Chiefs of Clanmaliere, a territory that lay on both sides of the river Barrow. It contained parts of Geashill and Phillipstown in Kings County and parts of Portnehinch in Queen's County. They claim descent through the O'Connors of Offaly, specifically the 2nd century Irish King, Cathair Mor. 2

According to O'Hart, they claim descent from through the "Connor" Faley pedigree.

Early History of the Dempser family

This web page shows only a small excerpt of our Dempser research. Another 286 words (20 lines of text) covering the years 1172, 1193, 1599, 1631, 1641, 1652 and 1865 are included under the topic Early Dempser History in all our PDF Extended History products and printed products wherever possible.

Dempser Spelling Variations

The Middle Ages saw a great number of spelling variations for surnames common to the Irish landscape. One reason for these variations is the fact that surnames were not rigidly fixed by this period. The following variations for the name Dempser were encountered in the archives: Dempsey, O'Dempsey, Dempsy, Dempsay, Dempsie and many more.

Early Notables of the Dempser family

Notable among the family name at this time was Sir Terence O'Dempsey, knighted May 1599, by Robert Devereux, earl of Essex, Lord Lieutenant of Ireland. Terence was created "Baron of Philipstown," and Viscount Clanmaliere, by patent dated 8th July, 1631, temp. Charles I. He had five sons, two of which were clergy:...
Another 52 words (4 lines of text) are included under the topic Early Dempser Notables in all our PDF Extended History products and printed products wherever possible.

Migration of the Dempser family

A great mass of Ireland's native population left the island in the 19th century, seeking relief from various forms of social, religious, and economic discrimination. This Irish exodus was primarily to North America. If the migrants survived the long ocean journey, many unfortunately would find more discrimination in the colonies of British North America and the fledgling United States of America. These newly arrived Irish were, however, wanted as a cheap source of labor for the many large agricultural and industrial projects that were essential to the development of what would become two of the wealthiest nations in the western world. Early immigration and passenger lists indicate many people bearing the Dempser name: Ann, Biddy, Bridget, Catherine, John, and Henry Dempsey who settled in Quebec in 1840; Edward Dempsey settled in New York in 1810; Jeremiah Dempsey settled in Mississippi in 1820.



  1. MacLysaght, Edward, Irish Families Their Names, Arms and Origins 4th Edition. Dublin: Irish Academic, 1982. Print. (ISBN 0-7165-2364-7)
  2. O'Hart, John, Irish Pedigrees 5th Edition in 2 Volumes. Baltimore: Genealogical Publishing Company, 1976. Print. (ISBN 0-8063-0737-4)


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