Joshua gave portions of land to the tribe of Levi, although the land was dispersed among the other tribes, and in the following description, you will see two cities of refuge,

Also to the children of Gershon, of the families of the Levites, from the other half-tribe of Manasseh, they gave Golan in Bashan with its common-land (a city of refuge for the slayer)…and from the tribe of Issachar…and from the tribe of Asher…and from the tribe of Naphtali, Kedesh in Galilee with its common-land (a city of refuge for the slayer)…All the cities of the Gershonites according to their families were thirteen cities with their common-lands” (Joshua 21:27–33).

Remember the cities of refuge existed for the person who accidentally killed someone. Such a person could go to that city to be protected from the dead person’s family, who might want to exact revenge, but because they had no right to do so, the survivor could flee to that city.

The Lord gave three cities on the West side of the Jordan, and as a sign that He had given them all the land, He would give them three cities of refuge on the East side of the Jordan.

In the text above, you see that the Levites had charge of those cities, because the Lord showed compassion to His people.