It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "A woman must not travel three miles except with her husband or a mahram." It was said to Ibn Abbas (may Allah be pleased with them both): "The people say three days." He said: "That is merely their mistake."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12598