This is piece of the 1930 U.S. Federal Census for Westbrook, Maine. Note that the address is 85 Haskell Street. Agnes Quigley was my great-great-grandmother. Living with her is Ethylle M. Gammon. How are they related? Well, I know. Agnes's daughter married Ethylle's first cousin. My great-grandparents were Lila Quigley and A.T. Pratt, the son of J.T. Pratt and Elizabeth Stack. Ethylle was the daughter of Charles Gammon and Mary Ann Stack.
So, it pays to some research on the siblings of all your direct ancestors.
P.S. How did Ancestry index this? Under Agnes J. Inigley. I've corrected it of course. As I always do . . . .