The cities of refuge were six Levitical towns in the Kingdom of Israel and the Kingdom of Judah in which the perpetrators of accidental manslaughter could claim the right of asylum. Maimonides, invoking talmudic literature, expands the city of refuge count to all 48 Levitical cities.
Outside of these cities, blood vengeance against such perpetrators was allowed by law. The Bible names the six cities of refuge as follows: Golan, Ramoth, and Bosor to the east of the Jordan River; and Kedesh, Shechem, and Hebron on the western (right) side.
Fleeing to the City of Refuge (Numbers 35:11–28). From Charles Foster, The Story of the Bible, 1884.
In the Hebrew Bible, the Levitical cities were 48 cities in ancient Israel set aside for the tribe of Levi, who were not allocated their own territorial land when the Israelites entered the Promised Land.
Cities of Refuge (illustration from a Bible card published 1901 by the Providence Lithograph Company)