Said to be named after Ralph Patchen, a 19th-century Brooklyn landowner.
According to Forgotten New York, Ralph Avenue's namesake is Ralph Patchen, a 19th-century landowner; Patchen Avenue runs one block to the west. Ralph Avenue was the eastern end of the original Eastern Parkway, after a row of avenues named for New York State cities from Kingston to Buffalo, but unlike them it is not named after a place.