Six cities of refuge were designated throughout Israel in Old Testament times to provide a haven for people who killed other persons by accident. Protection like this was necessary because of the avenger of blood, the relative who considered it his duty to slay the killer. Eligibility for refuge was determined by a judge. For convenience, three of the cities were located on either side of the Jordan River.
Thomas Nelson Publishers. (1996). Nelson’s complete book of Bible maps & charts : Old and New Testaments. (Rev. and updated ed.). Nashville, Tenn.: Thomas Nelson.