Sean Penn's mother, Eileen Ryan Penn (née Eileen Annucci, of Italian and Irish ancestry), said this
about the origin of her father-in-law Maurice's surname:
They asked for (Maurice's) name at Ellis Island, he said 'Piñon,' with his accent, and they said 'What? OK, Penn.'"
First of all, it's a myth
that immigrants' names were changed at Ellis Island. Second, Maurice never set foot on Ellis Island, unless as a tourist.
Maurice Daniel Penn was born Moische Pinon, 12 Oct. 1897 in Meretz, Russia (now Merkinė, Lithuania), and died
4 Mar. 1981 in Orange County, California. He arrived in Boston, Massachusetts
, aboard the S.S. Franconia
on 29 July 1914. He did change his name to "Penn" by 12 Sept. 1918, when he registered for the draft
Sean Penn does have plenty of Ellis Island ancestors, though. Maurice's mother, Bebka Pinon, passed through
in 1921, as did his wife Elizabeth Marion (née Lea) Melincoff, who came as a child with her mother and two siblings
on 5 Apr. 1897, aboard the S.S. Pennsylvania
. Elizabeth's father, "Mosche Malinkoff," came through
in August 1892.
Corrections and additions are welcome in the comments.