Numbers 35:3-5

3The Levites must have towns to live in and land for their cows and all their animals.

4The fields that you give to them for their animals must reach 500 metres from the walls of each town.

5You must also measure 1,000 metres outside the town on each side, the east side, the south side, the west side and the north side. So the town will be in the centre. Those fields of grass will belong to them for each of their towns.