Here is an interesting twist: Irish descendants in the U.S. are sending DNA kits to find out more about their roots in the Co. Galway Gaeltacht (Irish-speaking district).
The Maine Gaeltacht Project, linked with the Emigration and Diaspora Centre Project in Carna, Co. Galway, is funding DNA testing for Galway locals in an attempt to link members with their Irish families. The Maine Irish found that groups of Irish immigrants from the same townland or county would cluster together when they arrived in the US. That is true of Maine too. That means many of those with Irish roots living in the Portland, Maine, area can trace their family history back to the Connemara Gaeltacht.
You can read more in an article by Frances Mulraney in the IrishCentral web site at: https://www.irishcentral.com/roots/maine-irish-galway-dna-testing.