Many correspondents ask if they are descended from Judge Samuel Sewall of Boston. While some are, the odds are that most Sewalls are not.
All male descendants of the Massachusetts Sewall family are descended from three brothers: Judge Samuel of Boston (1652-1730); John Sewall of Newbury (1654-1699); and Stephen Sewall of Salem (1657-1725). In the eighth generation of the family in North America (the one I am currently editing for the forthcoming second volume), the three brothers are represented as follows:
Samuel: 10 male Sewall heads of household; John: 90 heads; Stephen: 18 male Sewell heads - descended from Jonathan Sewell of Canada. Stephen: 2 male Sewall heads of household
All male Sewall living descendants of Henry Sewall of Newbury, Mass., are descended from one of the above 120 men, and three-quarters of these eighth generation Sewalls are descended from the middle brother.
Even though descendants of Sewall daughters are not included in the study, I imagine the pattern would remain the same even if those lines were included. The three Sewall brothers had five sisters, each of who raised large families; there are therefore probably more descendants of Henry Sewall who are not descended from any of the brothers than who are.