Born in 2980 3A, Rosie lived with her family on South Lane, a farm near Bywater. Rosie and her siblings enjoyed to swim around the Bywater Pool. Her family was always close to the Gamgees, which was probably why she grew close to Samwise Gamgee. The two were already close friends with Rosie expecting a marriage proposal when Sam left the Shire, apparently for Crickhollow.