Cusco or Cuzco is a city in southeastern Peru, near the Sacred Valley of the Andes mountain range and the Huatanay river. It is the capital of …Cusco or Cuzco is a city in southeastern Peru, near the Sacred Valley of the Andes mountain range and the Huatanay river. It is the capital of the eponymous province and department. The city is the seventh most populous in Peru; in 2017, it had a population of 428,450. Its elevation is around 3,400 m.