First found in Italy, where bearers of Rosan were found since the Middle Ages in many areas of Italy, including Venetia, Emilia and the south. The spelling variations on the name which end in "o" are mostly from the south, whereas those that end in "i" are mostly from the north. The name Rosan, like many Italian surnames began as a personal name long before it was adopted as a surname; the name means "rose."

Some of the first settlers of this family name or some of its variants were: Giovanni Di Rosa and Pitata Rosa, who both arrived in New York January 7; 1881 aboard the SS Vincenzo Florio from Palermo, as well as Angleo DeRosa, who sailed on the Orsola, arriving in New York March 8.

For more information on the last name Rosan, the PDF Surname History is available for purchase as well as other products.