The focus of this paper will be to gain an insight to the genetic haplogroups or lineages of Irish Terrys; those from counties Cork and Waterford. These are the counties where most Terrys came from in former times. Several testers from the United States, Ireland and Peru have their results on the web. One of the United States participants and the sole participant living in Peru, have Spanish Terry ancestry. The fact that the Spanish Terrys of Cadiz descended from Cork Terrys and in the case of one lineage, Terrile from Italy, is well documented.

New insights to several Cork and Waterford Terry lineages, based on genetic data in combination with traditional genealogy are outlined. It also provides new insight to related lineages who settled in other parts of the world in recent centuries. Genetic time lines show the locational European origins of these lineages. How this information compares with what traditional genealogy said about these lineages is commented on. Some of the shortfalls in this approach in explaining Terry family history is considered.