Isabella was born on 10 Jan 1808 to Joseph Mainville and Cree Indian woman Josette (Josie).
She originally came here with her husband who was employed by the Hudson's Bay Company as Chief Factor (Chief Trader) who was in charge of building Fort Victoria, a fur trading post and the headquarters of Hudson's Bay Company operations in British Columbia. The fort was the beginnings of a settlement that grew into the modern Victoria, the capital city of British Columbia.
Isabella Ross was the first woman to own property in British Columbia. After her husband's death Isabella bought land for a farm that now makes up the eastern two-thirds of Ross Bay Cemetery, where she is buried. Not only is Ross Bay named for her but she also named Foul Bay, though it was originally spelled "Fowl".
Isabella died at St. Anne's convent in 1885 at age 77 years.