Sunan Abi Dawud, Hadith 1723 ⓘ
Ibn `Umr reported the Prophet (SWAS) as saying : A woman must not make a journey of three days unless she is accompanied by a man who is within the prohibited degree.
حَدَّثَنَا أَحْمَدُ بْنُ حَنْبَلٍ، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ عُبَيْدِ اللَّهِ، قَالَ حَدَّثَنِي نَافِعٌ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " لاَ تُسَافِرُ الْمَرْأَةُ ثَلاَثًا إِلاَّ وَمَعَهَا ذُو مَحْرَمٍ " .
also referenced under: Hadith 1727 (DarusSalam)