I heard Abu Sa'id al-Khudri (Allah be pleased with him) saying: I heard four things from Allah's Messenger (ﷺ) which impressed me and captivated me (and one out of these is this), that he forbade a woman to undertake journey extending over two days but with her husband, or with a Mahram; and he then narrated the rest of the hadith.
Sahih Muslim Book 15, Hadith 466
← Previous Hadith I heard a hadith from Abu Sa'id (Allah be pleased with him) and it impressed me (very much), so I said to him: Did you hear it (yourself) from Allah's Messenger (ﷺ)? Thereupon he said: (Can) I speak of anything about Allah's Messenger (ﷺ) which I did not bear? He said: I heard Allah's Messenger (ﷺ) saying: Do not set out on a journey (for religious devotion) but for the three mosques-for this mosque of mine (at Medina) the Sacred Mosque (at Mecca), and the Mosque al-Aqsa (Bait al-Maqdis), and I heard him saying also: A woman should not travel for two days duration, but only when there is a Mahram with her or her husband.

Sahih Muslim Book 15, Hadith 465 Next Hadith → A woman should not set out on three (days') journey, but in the company of a Mahram.

Sahih Muslim Book 15, Hadith 467