What is the distance a woman may travel without a mahram, and is it permissible for women to travel together in a rented bus without a mahram?

The Prophet, may Allah’s prayers and peace be upon him, forbade women from traveling without a mahram. Islamic law has not specified a particular distance for travel; rather, any journey considered travel by custom is prohibited for a woman without a mahram. This prohibition includes both a woman traveling alone and a group of women.