'Cities of the Levites' in the Bible

As for the cities of the Levites, the houses in the cities which they possess, the Levites must have a perpetual right of redemption.

Whatever someone among the Levites might redeem -- the sale of a house which is his property in a city -- must revert in the jubilee, because the houses of the cities of the Levites are their property in the midst of the Israelites.