Al-Lu'lu Wal-Marjan 847 — The Book of Hajj (Pilgrimage to Makka)

Narrated Ibn 'Umar رضى الله عنهما: The Prophet ﷺ said, "A woman should not travel for more than three days except with a Dhû-Mahram (i.e. a male with whom she cannot marry at all, e.g. her brother, father, grandfather... etc., or her own husband)." ( Sahîh Al-Bukhârî, Hadîth No. 192, Vol. 2)