Cemetery notes and/or description from Find-a-Grave:
"Located on land that was once the Willis Farm.
"Number 11 in the Historic Cemeteries of Oyster Bay guide."
Early records describe this as Willis Farm Cemetery, located in Wheatley, Queens Co., New York. (This area of Queens became Nassau County in 1899.) It is assumed the East Hill reference is to a post office designation, not the physical location.