These are the boundaries around the people of Judah by their clans.

 Joshua 15:1-19

These are the boundaries around the people of Judah by their clans.

In accordance with the Lord’s command to him, Joshua gave to Caleb son of Jephunneh a portion in Judah—Kiriath Arba, that is, Hebron.  From Hebron Caleb drove out the three Anakites—Sheshai, Ahiman and Talmai, the sons of Anak. From there he marched against the people living in Debir (formerly called Kiriath Sepher). And Caleb said, “I will give my daughter Aksah in marriage to the man who attacks and captures Kiriath Sepher.” Othniel son of Kenaz, Caleb’s brother, took it; so Caleb gave his daughter Aksah to him in marriage.

One day when she came to Othniel, she urged him  to ask her father for a field. When she got off her donkey, Caleb asked her, “What can I do for you?” She replied, “Do me a special favor. Since you have given me land in the Negev, give me also springs of water.” So Caleb gave her the upper and lower springs.

Judah's cities included those of Caleb - and also Jerusalem, or part of it. But the city was still unconquered much later, at the time of writing. 

Why?

The land of Judah seems huge, but there are many cities that were still unconquered.

Othniel is courageous and can fight for Caleb's daughter so he got it. Later Othniel became the Judge of Israel.

Caleb has the important city Jerusalem for his faithful to the Lord.

Caleb not only gets the city but also has a son-in-law.

How?

The Lord blesses those who obey the word of the Lord.