his paternal grandparents were moreau delano and sarah ann (née abrams) delano. he was a distant cousin of president franklin delano roosevelt. through his maternal aunt, mary elizabeth adams brown, he was the nephew of john crosby brown, the head of brown brothers & company. mary elizabeth adams(brown) was the minister william adams sister, who was delano's maternal grandfather, and for whom he was named after. the minister william adams wife was martha bradshaw magoun, who was the maternal grandmother of delano, and she was the daughter of thatcher magoun (associated with the [[thatcher magoun (clipper)|"thatcher magoun" clipper]] and [[60 state street]]) and mary bradshaw. previously the minister william adams was married to susan patten magoun, sister of martha bradshaw, before susan patten died. a further connection between the families resides in the offspring of john crosby brown and mary elizabeth's six children, with a son thatcher magoun brown named in honor of thatcher magoun, along with daughter mary magoun brown, and their eldest child william adams brown, who like delano was also named in honor of their grandfather the minister william adams. furthermore, delano's father eugene had made partner with the philadelphia house of brown brothers & co., meanwhile his mothers middle name is magoun.