The project is open to persons whose paternal or maternal lineage originated in the British Isles. Members may have have identified a county of origin for a direct maternal or paternal lineage ancestor in the British Isles, or may be searching for the origin of their direct paternal and/or maternal lineages in the British Isles. If you have identified a county of origin in the British Isles, you are asked to supply this information when you apply for membership and on your MyFTDNA page.

The term "direct lineage" refers to either the Y-DNA ascending lineage (father's father's... father) on the paternal side, or the mtDNA ascending line (mother's mother's... mother) on the maternal side.