Often times the stronghold, or strong tower in times of battle was positioned at the top of a hill. This gave an elevated vantage point and the people were able to see from a broader point of view, giving early warning of approaching enemies. Of course being used as a place of protection it was also used as a place of provision, having food and supplies ready to go when the situation arose.
Psalm 18:1-2- I will love You, O Lord, my strength. The Lord is my rock and my fortress and my deliverer; My God, my strength, in whom I will trust; My shield and the horn of my salvation, my stronghold.
Psalm 27:1- The Lord is my light and my salvation; whom shall I fear? The Lord is the stronghold of my life; of whom shall I be afraid?
Proverbs 18:10- The name of the Lord is a strong tower; The righteous run to it and are safe.