Riyad as-Salihin 989
Abu Hurairah (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) said, "It is not permissible for a woman who believes in Allah and the Last Day to make a journey of one day and night unless she is accompanied by a Mahram (husband or any other relative to whom she is prohibited to marry)." [Al-Bukhari and Muslim] .
عن أبي هريرة رضي الله عنه قال‏:‏ قال رسول الله صلى  الله عليه وسلم  ‏:‏ ‏
"‏لا يحل لامرأة تؤمن بالله واليوم الآخر تسافر مسيرة يوم وليلة إلا مع ذي محرم عليها‏"‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏ ‏.‏