A hillfort is a kind of fortified settlement, usually built at the top of a hill, supported by earthworks (usually ditches and mounds of earth). Hillforts would use this elevated position as defense and protection. Wooden walls would have been used as an extra defense.
Once inside, the hillfort would look very similar to a town. A hillfort could be a home to hundreds of people, with churches, markets, and military camps. The hillfort was an excellent way of keeping a town safe.