To the south is the Norte Chico, extending to the Aconcagua river. Los Andes begin to decrease its altitude to the south and closer to the coast, reaching 90 km away at the height of Illapel, the narrowest part of the Chilean territory. The two mountain ranges intersect, virtually eliminating the intermediate depression. The existence of rivers flowing through the territory allows the formation of transverse valleys, where agriculture has developed strongly in recent times, while the coastal plains begin to expand.