Dewees family historians report that this family name in America derives primarily from a single immigrant family in the 17th century. The principal goal of the Dewees Surname Project, initiated on June 7, 2010, is to use Y chromosome variations in Dewees(e) males to test the hypothesis that virtually all Dewees families in America are descended from a single ancestral male, most likely Garrett Hendricks de Wees who immigrated to New Amsterdam (New York City)in 1663. A secondary goal is to determine if Dewees families sort out into specific sub groups. Once a new Y-chromosome mutation occurs in a Dewees male, his Dewees male descendants should carry this rare and unique mutation and would therefore form a distinctive sub group of the Dewees family. Through participation in this project by male Deweeses having extensive records of their families back to Garrett Hendricks deWees, we will be able to associate variations in Y chromosomes with the different Dewees lineages in America.