Some of the descendants of Judah and Benjamin lived in Jerusalem. From Judah's Descendants: Uzziah's son Athaiah, who was the son of Zechariah, the son of Amariah, the son of Shephatiah, the son of Mahalalel; From Perez's Descendants

As for the farming settlements with their fields:

Some of Judah’s descendants lived in Kiriath-arba and its villages,
Dibon and its villages, and Jekabzeel and its villages;

Zichri's son Joel was their overseer, and Hassenuah's son Judah was in command of the second district of the city.

I found a register of the original inhabitants in which there was recorded a list of descendants of the province of Judah who returned from captivity, from those who had been exiled by Nebuchadnezzar king of Babylon. They had come back to Jerusalem and to Judah, each one to his town.

And Pethahiah the son of Meshezabeel, of the children of Zerah the son of Judah, was at the king's hand in all matters concerning the people.

Now these are the chief of the province that dwelt in Jerusalem: but in the cities of Judah dwelt every one in his possession in their cities, to wit, Israel, the priests, and the Levites, and the Nethinims, and the children of Solomon's servants.

and have even set up the prophets in Jerusalem to proclaim on your behalf: “There is a king in Judah.” These rumors will be heard by the king. So come, let’s confer together.

During those days, the nobles of Judah sent many letters to Tobiah, and Tobiah’s letters came to them.