The Haldane (Hadden, Halden) families originated in Scotland, perhaps from Roger de Hadden, the earliest ancestor found in written records. Joining this study will help determine Haldane and Hadden progenitors. There are at least two Haplogroups (I and R1b) represented by the Haldane name. This study may also connect Hadden and Haldane family members separated in genealogy by phonetic spelling of the surname in the 19th century and earlier. Famous Haldanes include genetic scientist JBS Haldane, John Scott Haldane, Viscount Haldane, Elizabeth Sanderson Haldane, and many more involved in science, politics, philosophy, and other disciplines. The northern Ireland Haddens are documented to c. 1766-1767 in Aghaloo and Carnteel parishes, County Tyrone, Ireland (now Northern Ireland). Earlier ancestors were said to have come from Aberdeen, Scotland, per an 1866 letter written by David HADDEN, born 1809 Ballygawley, Co. Tyrone, as well as stated on his nephew Joseph Hadden Calvin's biographical records at Princeton University. We welcome all participants and hope you will aid us by joining in this exciting journey!