Verses with the word castles in the Old Testament (6 verses):

Genesis 25:16
These are the sons of Ishmael, and these are their names, by their towns, and by their castles; twelve princes according to their nations.

Numbers 31:10
And they burnt all their cities wherein they dwelt, and all their goodly castles, with fire.

1 Chronicles 6:54
Now these are their dwelling places throughout their castles in their coasts, of the sons of Aaron, of the families of the Kohathites: for theirs was the lot.

1 Chronicles 27:25
And over the king's treasures was Azmaveth the son of Adiel: and over the storehouses in the fields, in the cities, and in the villages, and in the castles, was Jehonathan the son of Uzziah:

2 Chronicles 17:12
And Jehoshaphat waxed great exceedingly; and he built in Judah castles, and cities of store.

2 Chronicles 27:4
Moreover he built cities in the mountains of Judah, and in the forests he built castles and towers.