First found in County Clare, where they held a family seat from very ancient times. 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.

Ireland experienced a dramatic decrease in its population during the late 19th century. This was in a great measure, a response to England's imperialistic policies. Hunger and disease took the lives of many Irish people and many more chose to leave their homeland to escape such hunger and disease. North America with its promise of work, freedom, and land was an extremely popular destination for Irish Families. For those families that survived the journey, all three of these things were were often attained through much hard work and perseverence. Research into early immigration and passenger lists revealed many immigrants bearing the name Dagen: 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.

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