Judah Receives Southern Canaan, and Caleb Conquers His Territory
Partly as a result of the land Caleb chose for himself (verse 13), the inheritance of the tribe of Judah is assigned to be the southern part of the Canaanite territory. This was essentially the territory south of Jericho and Jerusalem, which had been the land conquered primarily in chapter 10. It is the land Judah continued to hold following the division of the monarchy in the days of Rehoboam nearly 500 years later.
Caleb finishes conquering his territory and ridding it of the giants (verse 14). In the process, he takes Debir, a city that had originally been taken by Joshua (10:38-39) but had evidently fallen back into the hands of the Canaanites. He receives some assistance from his nephew Othniel (verse 17), who will later serve as the first judge following the death of Joshua (Judges 3:7-11 Judges 3:7-11  And the children of Israel did evil in the sight of the LORD, and forgot the LORD their God, and served Baalim and the groves.
 Therefore the anger of the LORD was hot against Israel, and he sold them into the hand of Chushanrishathaim king of Mesopotamia: and the children of Israel served Chushanrishathaim eight years.
 And when the children of Israel cried to the LORD, the LORD raised up a deliverer to the children of Israel, who delivered them, even Othniel the son of Kenaz, Caleb’s younger brother.
 And the Spirit of the LORD came on him, and he judged Israel, and went out to war: and the LORD delivered Chushanrishathaim king of Mesopotamia into his hand; and his hand prevailed against Chushanrishathaim.
 And the land had rest forty years. And Othniel the son of Kenaz died.
American King James Version×). Much of this story is repeated in Judges 1:10-15 Judges 1:10-15  And Judah went against the Canaanites that dwelled in Hebron: (now the name of Hebron before was Kirjatharba:) and they slew Sheshai, and Ahiman, and Talmai.  And from there he went against the inhabitants of Debir: and the name of Debir before was Kirjathsepher:  And Caleb said, He that smites Kirjathsepher, and takes it, to him will I give Achsah my daughter to wife.  And Othniel the son of Kenaz, Caleb’s younger brother, took it: and he gave him Achsah his daughter to wife.  And it came to pass, when she came to him, that she moved him to ask of her father a field: and she lighted from off her ass; and Caleb said to her, What will you?  And she said to him, Give me a blessing: for you have given me a south land; give me also springs of water. And Caleb gave her the upper springs and the nether springs.
American King James Version×. While the city of Hebron itself is given to the priests (Joshua 21:9-13 Joshua 21:9-13  And they gave out of the tribe of the children of Judah, and out of the tribe of the children of Simeon, these cities which are here mentioned by name.  Which the children of Aaron, being of the families of the Kohathites, who were of the children of Levi, had: for theirs was the first lot.  And they gave them the city of Arba the father of Anak, which city is Hebron, in the hill country of Judah, with the suburbs thereof round about it.  But the fields of the city, and the villages thereof, gave they to Caleb the son of Jephunneh for his possession.  Thus they gave to the children of Aaron the priest Hebron with her suburbs, to be a city of refuge for the slayer; and Libnah with her suburbs,
American King James Version×), and serves as a city of refuge, the fields and suburbs are given to Caleb.