TSK · Numbers 26:54

So they said,“If we have found favor in your sight, let this land be given to your servants for our inheritance. Do not have us cross the Jordan River.”

The towns you will give must be from the possession of the Israelites. From the larger tribes you must give more; and from the smaller tribes fewer. Each must contribute some of its own towns to the Levites in proportion to the inheritance allocated to each.

Simeon’s assigned land was taken from Judah’s allotted portion, for Judah’s territory was too large for them; so Simeon was assigned land within Judah.