Complex sentence: Sørlandet is the geographical region ("landsdel") of the Skagerrak coast of southern Norway consisting of the two counties Vest-Agder and Aust-Agder.
Split into simpler sentences: Sørlandet is the geographical region ("landsdel") of the Skagerrak coast of southern Norway. Regarding Sørlandet as a region, it means the two counties Vest-Agder and Aust-Agder.