The Prophet ﷺ said, "A woman should not travel for more than three days except with a Dhi-Mahram."  

عَنِ النَّبِيِّ ﷺ قَالَ لاَ تُسَافِرِ الْمَرْأَةُ ثَلاَثًا إِلاَّ مَعَ ذِي مَحْرَمٍ  

Abu Saʿid who participated in twelve Ghazawat with the Prophet ﷺ said, "I heard four things from Messenger of Allah ﷺ (or I narrate them from the Prophet ﷺ ) which won my admiration and appreciation. They are: -1. "No lady should travel without her husband or without a Dhu-Mahram for a two-days' journey. -2. No fasting is permissible on two days of ʿId-ul-Fitr, and ʿId-al-Adha. -3. No prayer (may be offered) after two prayers: after the ʿAsr prayer till the sun set and after the morning prayer till the sun rises. -4. Not to travel (for visiting) except for three mosques: Masjid-al-Haram (in Mecca), my Mosque (in Medina), and Masjid-al-Aqsa (in Jerusalem).  

سَمِعْتُ أَبَا سَعِيدٍ وَقَدْ غَزَا مَعَ النَّبِيِّ ﷺ ثِنْتَىْ عَشْرَةَ غَزْوَةً قَالَ أَرْبَعٌ سَمِعْتُهُنَّ مِنْ رَسُولِ اللَّهِ ﷺ أَوْ قَالَ يُحَدِّثُهُنَّ عَنِ النَّبِيِّ ﷺ فَأَعْجَبْنَنِي وَآنَقْنَنِي أَنْ لاَ تُسَافِرَ امْرَأَةٌ مَسِيرَةَ يَوْمَيْنِ لَيْسَ مَعَهَا زَوْجُهَا أَوْ ذُو مَحْرَمٍ وَلاَ صَوْمَ يَوْمَيْنِ الْفِطْرِ وَالأَضْحَى وَلاَ صَلاَةَ بَعْدَ صَلاَتَيْنِ بَعْدَ الْعَصْرِ حَتَّى تَغْرُبَ الشَّمْسُ وَبَعْدَ الصُّبْحِ حَتَّى تَطْلُعَ الشَّمْسُ وَلاَ تُشَدُّ الرِّحَالُ إِلاَّ إِلَى ثَلاَثَةِ مَسَاجِدَ مَسْجِدِ الْحَرَامِ وَمَسْجِدِي وَمَسْجِدِ الأَقْصَى  

The Prophet ﷺ said, "It is not permissible for a woman who believes in Allah and the Last Day to travel for one day and night except with a Mahram."  

قَالَ النَّبِيُّ ﷺ لاَ يَحِلُّ لاِمْرَأَةٍ تُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ أَنْ تُسَافِرَ مَسِيرَةَ يَوْمٍ وَلَيْلَةٍ لَيْسَ مَعَهَا حُرْمَةٌ  

That he heard the Prophet ﷺ saying, "It is not permissible for a man to be alone with a woman, and no lady should travel except with a Muhram (i.e. her husband or a person whom she cannot marry in any case for ever; e.g. her father, brother, etc.)." Then a man got up and said, "O Messenger of Allah ﷺ! I have enlisted in the army for such-and-such Ghazwa and my wife is proceeding for Hajj." Messenger of Allah ﷺ said, "Go, and perform the Hajj with your wife."  

أَنَّهُ سَمِعَ النَّبِيَّ ﷺ يَقُولُ لاَ يَخْلُوَنَّ رَجُلٌ بِامْرَأَةٍ وَلاَ تُسَافِرَنَّ امْرَأَةٌ إِلاَّ وَمَعَهَا مَحْرَمٌ فَقَامَ رَجُلٌ فَقَالَ يَا رَسُولَ اللَّهِ اكْتُتِبْتُ فِي غَزْوَةِ كَذَا وَكَذَا وَخَرَجَتِ امْرَأَتِي حَاجَّةً قَالَ اذْهَبْ فَحُجَّ مَعَ امْرَأَتِكَ