In | The Inheritance of the Tribe of Levi, Part 1

The Levites don’t receive land like the other tribes. Instead they receive cities within the territory of other tribal allotments. We know the reason for this from the Pentateuch—the first five books of the Bible. 

Consider two passages that explain this situation, the first from Numbers: 

To the sons of Levi, behold, I have given all the tithe in Israel for an inheritance, in return for their service which they perform, the service of the tent of meeting. The sons of Israel shall not come near the tent of meeting again, or they will bear sin and die. Only the Levites shall perform the service of the tent of meeting, and they shall bear their iniquity; it shall be a perpetual statute throughout your generations, and among the sons of Israel they shall have no inheritance. For the tithe of the sons of Israel, which they offer as an offering to the Lord, I have given to the Levites for an inheritance; therefore I have said concerning them, “They shall have no inheritance among the sons of Israel.” 
Numbers 18:21-24 (NASB)