Deiman History, Family Crest & Coats of Arms
The ancient Gaelic form of the Irish name Deiman was O Dubhaigan. The first portion of the name is the word dubh, which means black; the second portion is likely some obsolete Irish personal name.
Early Origins of the Deiman family
The surname Deiman was first found in County Clare (Irish: An Clár) located on the west coast of Ireland in the province of Munster, where O'DuilAgin, O'Dugan, (or O'Deegan), chief of Muintir ConIochta, a district in the parish of Tomgraney, in the barony of Tullagh.
The family line is directly traceable to Fergus Mor (Fergus the Great). In turn his ancestry is associated with King Ir, brother of the equally famous Heremon. The name was first found near what is now the town of Fermoy, in the territory formerly known as Roche's Country. This territory encompassed the junction of the counties Cork, Tipperary and Waterford. In modern times, the surname is generally found in these three counties.
However, there was another O'Dugan sept in the territory called Ui Maine, also called Hy Many, which spans eastern county Galway and southern county Roscommon. This sept gave their name to the place called Ballyduggan, near Loughrea. 
Early History of the Deiman family
This web page shows only a small excerpt of our Deiman research. Another 155 words (11 lines of text) covering the years 1327, 1813, 1896, 1813, 1896, 1823 and 1884 are included under the topic Early Deiman History in all our PDF Extended History products and printed products wherever possible.
Deiman Spelling Variations
Many different spelling variations of the surname Deiman were found in the archives researched. These included Scribes and church officials generally spelled a name as it sounded; as a result, a person's name could be spelt innumerable ways in his lifetime. Dugan, Duggan, O'Duggan, Dougan, Douggan, Dewgan, Deugan and many more.
Early Notables of the Deiman family (pre 1700)
Another 29 words (2 lines of text) are included under the topic Early Deiman Notables in all our PDF Extended History products and printed products wherever possible.
Migration of the Deiman family
The 19th century brought a massive reduction in Ireland's population. It seemed that during the Great Potato Famine of the late 1840s the Irish people had two options: starve or immigrate. Those that chose the later frequently headed for the United States, hopeful for land, work, and equality. Those determined for free land joined the migration west; while others stayed behind to live in urban centers and often work in factories. Still others began a transitory life in work camps, building the bridges, canals, railways, and highways so critical to the rapidly development of the growing industrial nation. Early passenger and immigration lists have shown many early immigrants bearing the name Deiman: James Dugan who settled in New York State in 1775; John Duggen, who arrived in Maryland in 1739; Cornelius Duggin, who arrived in Albany, NY in 1762; John Duggin, who came to Boston in 1765.