Is it permissible for a woman to travel from one city to another within her country for several days for work without a mahram?

A woman is not permitted to travel for work or any other purpose, whether inside or outside the country, except with a mahram or her husband. This is based on the hadith: "No woman should travel except with a dhī mahram (a male relative she cannot marry)." Any journey that is considered travel is forbidden for a woman without her husband or a mahram.