Women - Traveling (Ahadith 891 - 893)


Assalamu`alaykum,
Bismillah.

Volume 2, Book 20, Number 192:
Narrated Ibn 'Umar:
The Prophet said, "A woman should not travel for more than three days except with a Dhi-Mahram (i.e. a male with whom she cannot marry at all, e.g. her brother, father, grandfather, etc.) or her own husband.)"

Volume 2, Book 20, Number 193:
Narrated Ibn'Umar:
The Prophet said, "A woman should not travel for more than three days except with a Mahram."

Volume 2, Book 20, Number 194:
Narrated Abu Huraira:
The Prophet (p.b.u.h) 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."

The saheeh (authentic) Sunnah indicates that it is not permissible for a woman to travel except with a mahram. This travelling is not defined by a specific distance, as is the case with shortening the prayers or breaking the fast, rather everything that is called travelling, whether it is long or short, is not permitted for a woman unless she has a mahram with her. 
Al-Bukhaari (1729) and Muslim (2391) narrated that Ibn ‘Abbaas (may Allaah be pleased with him) said: The Prophet (peace and blessings of Allaah be upon him) said: “No woman should travel except with a mahram.” 
The fuqaha’ are unanimously agreed that it is haraam for a woman to travel without a mahram, except in a few exceptional cases, such as travelling for the obligatory Hajj, for which some of them have permitted a women to travel with trustworthy companions. Al-Haafiz Ibn Hajar (may Allaah have mercy on him) said: al-Baghawi said: They did not differ concerning the fact that a woman may not travel for anything but the obligatory Hajj except with a husband or mahram, except a kaafir woman who becomes Muslim in daar al-harb or a female captive who escapes. Others added: or a woman who becomes separated from her group and is found by a trustworthy man, in which case it is permissible for him to accompany her until he brings her back to her group. End quote from Fath al-Baari (4/76). 


For a very detailed and satisfactory answer, including the wisdom and reasons behind this ruling, read this.
Wassalam.