Santa Rosa's history is rich in culture and many different groups have called the area their home. Pomo, Miwok, and Wappo Indians originally populated the area followed by the Spanish in the early 1800's. The first deeded land was held as the Rancho Cabeza de Santa Rosa and was given to Senora Maria Ignacia Lopez de Carrillo by Spanish authorities.

According to popular legend, this area was named Santa Rosa by Father Juan Amorosa. After baptizing a young Native American woman in a stream, he followed the usual custom of naming rivers and creeks for saints. Because the baptism took place on the day of the Feast of Santa Rosa de Lima, Santa Rosa was the name given to the stream (and later to the whole valley) as well as to the young woman who was baptized.