O'Dempsy History, Family Crest & Coats of Arms
- Origins Available:
Today's Irish surnames are underpinned by a multitude of rich histories. The name O'Dempsy originally appeared in Gaelic as O Diomasaigh, from the word "diomasach," which means "proud." 
Early Origins of the O'Dempsy family
The surname O'Dempsy 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. 
According to O'Hart, they claim descent from through the "Connor" Faley pedigree.
Early History of the O'Dempsy family
This web page shows only a small excerpt of our O'Dempsy research. Another 286 words (20 lines of text) covering the years 1172, 1193, 1652, 1865, 1599, 1631 and 1641 are included under the topic Early O'Dempsy History in all our PDF Extended History products and printed products wherever possible.
O'Dempsy Spelling Variations
Irish names were rarely spelled consistently in the Middle Ages. Spelling variations of the name O'Dempsy dating from that time include Dempsey, O'Dempsey, Dempsy, Dempsay, Dempsie and many more.
Early Notables of the O'Dempsy family (pre 1700)
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 O'Dempsy Notables in all our PDF Extended History products and printed products wherever possible.
Migration of the O'Dempsy family
A massive amount of Ireland's native population left the island in the 19th century for North America and Australia in hopes of finding more opportunities and an escape from discrimination and oppression. A great portion of these migrants arrived on the eastern shores of the North American continent. Although they were generally poor and destitute, and, therefore, again discriminated against, these Irish people were heartily welcomed for the hard labor involved in the construction of railroads, canals, roadways, and buildings. Many others were put to work in the newly established factories or agricultural projects that were so essential to the development of what would become two of the wealthiest nations in the world. The Great Potato Famine during the late 1840s initiated the largest wave of Iris immigration. Early North American immigration and passenger lists have revealed a number of people bearing the name O'Dempsy or a variant listed above: 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.
- MacLysaght, Edward, Irish Families Their Names, Arms and Origins 4th Edition. Dublin: Irish Academic, 1982. Print. (ISBN 0-7165-2364-7)
- O'Hart, John, Irish Pedigrees 5th Edition in 2 Volumes. Baltimore: Genealogical Publishing Company, 1976. Print. (ISBN 0-8063-0737-4)