The lagoon forms part of the Huascarán National Park and the Huascarán Biosphere Reserve.
Llanganuco Lagoon (which is comprised of two lagoons: the Warmicocha or female lagoon and the Orcococha or male lagoon) is formed by the thawing of the ice from two of the most emblematic mountains in Áncash: Huascarán and Huandoy.
The first lagoon, Chinancocha, is 1,450 metres long, 7,393 metres wide and 28 metres deep. On the shores of Chinancocha there are queñual trees and totora reeds as well as wild ducks. This is the most popular and most visited lagoon.
The second lagoon, Orcococha, is located at the end of the valley and is 910 metres long, 368 metres wide and seven metres deep. Its waters, like those of Chinancocha, flow into the River Ranrahirca, and eventually join the River Santa (Saintly River). This second lagoon is a good place to see the wild ducks of the region.