By the early 18th century the Irish were the largest immigrant group to settle in the thirteen colonies. During this period the majority of emigrants to America were Presbyterians from the north or Ireland, though this changed dramatically in the 19th century. The greatest Irish exodus to America occurred between the end of the Napoleonic Wars in 1815 and the conclusions of the potato famine in 1851. During this span, around one million left Ireland, mainly for North America. Most of those bound for North America sailed from Irish ports, though others went via Liverpool or Glasgow.

This volume is based on primary sources located in Ireland, the U.S., Canada, Scotland, England, and the West Indies. Such primary sources include manuscripts, newspapers and journals, monumental inscriptions, and government records.