Ancash (pronounced: [ˈaŋ.kaʃ]) is a region in northern Peru. It is bordered by the La Libertad region on the north, the Huánuco and Pasco regions on the east, the Lima region on the south, and the Pacific Ocean on the west. Its capital is the city of Huaraz, and its largest city and port is Chimbote. The name of the region originates from the Quechua word anqash, which means blue.

Ancash is a land of contrasts. It has two, great longitudinal valleys, which combine the mountain characteristics of the Callejón de Huaylas (Alley of Huaylas) with the sylvan ones of the Alto Marañón. Miles of sandy beaches abut the blue waters of the Pacific. The territory of the coast, high plateaus and Andean punas of the Ancash Region are flat, while the rest of the territory, in the Andes, is very rough. In the west, slopes with strong declivity form narrow canyons with abrupt and deserted sides.

The rough territory of the region is crossed by two mountain ranges: on the western side, the Cordillera Negra (the Black Mountain Range), which has peaks without glaciers, and on the eastern side, the Cordillera Blanca (the White Mountain Range), which has many peaks covered with snow and ice, like the Huascarán and the Alpamayo. Between these two mountain ranges, the Santa River flows through the so-called Callejón de Huaylas. This alley narrows to form the Cañón del Pato (Duck Canyon). Also along the Pacific slopes, the Santa River has shaped a wide valley in the punas which narrows into the Cordillera Negra where the Cañón del Pato canyon was formed.