Rosa was born on TA 2856 (SR 1256) and was an ancestor of both Merry and Pippin. Rosa was the daughter of Ponto Baggins and Mimosa Bunce. She had a younger brother, Polo. Her husband was Hildigrim Took (TA 2840 – TA 2941), one of the many sons of the Old Took. They had one child, Adalgrim Took.
- The Lord of the Rings: Appendix C, "Baggins of Hobbiton"
- The Lord of the Rings: Appendix C, "Took of Great Smials"