Huayhuash[1][2][3] (possibly from Quechua waywash, weasel,[4] or waywashi, squirrel)[5] is a mountain range within the Andes of Peru, in the boundaries of the regions of Ancash, Lima and Huánuco.

[citation needed] Some mining takes place in the area, so to the north of the mountains there is an unsurfaced road leading up to as high as 4750 m.[citation needed] In 2002, the Peruvian Ministry of Agriculture declared the Huayhuash mountain range a "reserved zone" and prohibited certain economic activities, including any future mining.

[11][12] Most of the walking and most of the campsites are above the 4,000 m tree line, so the landscape appears rugged and mountainous, affording views over very wide areas.

Trekking is almost always undertaken in the dry winter months of May to September, and the cities Huaraz and Caraz over 100 & 167 km away are the usual choice for organizing and hiring camping a/o logistical support.

[13] But nowadays, daily buses (locally called colectivos) go deep into the mountains to the village Llamaq (3,300 m) and with private transport, as far as Cuartelwain camp, reached both by road built in the late 90s and 2000s, becoming now the new trail heads for starting/ending.

These sedimentary rocks originated as deposits on the ocean floor and were subsequently uplifted and folded due to tectonic plate convergence.

In the late 1980s a party of European trekkers were robbed and ordered to return to Huaraz with the message that future intruders would be killed.

Near the north shore of the lake Viconga, the remains of an old Shining Path base camp can be still visited, including a shooting range, barracks and a training field.