What is duggan last name origin?

Duggan is a Celtic surname that originated in Ireland. The name is derived from the Gaelic word "dubhagán," which means "little black-haired one" or "dark-haired one." The name is most commonly found in the western regions of Ireland, particularly in counties Clare and Galway. Variations of the name include Duggin, Duggen, Dugan, and Dougan.