First found in Connacht, and Leinster. The name became confused with Coen, Kyne, and Kilcoyne, all of which have derived from it, or have been the origin of Coyne. The ancient Coens, descended from the Gaelic Caomhan, the Chief of his clann in 876 A.D. who was descended from the Princes of Hy Fiachra, and the great General King Niall of the Nine Hostages.

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 Cohn name: John Adam Barnacle who arrived in Pennsylvania in 1772; Patrick Coyne settled in Philadelphia in 1813; John, Joseph, Lawrence, Michael, Patrick, Peter, Thaddeus, Thomas, and William Coyne, all arrived in Philadelphia between 1850 and 1870.

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