Deuteronomy 4:41-43

41Then Moses set aside three cities across the Jordan to the east 42to which a manslayer could flee after killing his neighbor unintentionally without prior malice.

To save one’s own life, he could flee to one of these cities: 43Bezer in the wilderness on the plateau belonging to the Reubenites, Ramoth in Gilead belonging to the Gadites, or Golan in Bashan belonging to the Manassites.