Lake Junín

Lake Junín, also called Chinchaycocha, covers around five hundred square kilometres of the high plateau at 4,080 metres, making it the largest lake entirely inside Peru, and it is shallow - a few metres at most - with vast reed beds around its margins. It is a national reserve mainly because of the Junín grebe, a flightless diving bird that exists only on this lake and nowhere else on earth, with a population that has fallen to a few hundred and is monitored closely; the Junín rail is likewise endemic to these marshes. Both are threatened by the same thing: water levels manipulated for hydroelectric generation, and a century of heavy metal contamination from mining at Cerro de Pasco and along the feeder rivers, which has left parts of the lake badly polluted. Visits are made by boat from shore villages with local guides, and the birdlife beyond the endemics is substantial.

What you actually see

• The lake - around five hundred square kilometres at 4,080 metres, only metres deep.
• The Junín grebe - a flightless bird found on this lake alone, down to a few hundred.
• The reed beds - vast marshes around the margins holding the endemic rail.
• The pressures - regulated water levels and mining contamination from upstream.

When to go

May to September for weather and access. Mornings are calmest for boats. Half a day to a day with a guide from Ondores, Pari or Junín.

Honest expectations

At 4,080 metres it is cold, windy and exhausting for the unacclimatised. The grebe is scarce and needs a knowledgeable guide and binoculars. Parts of the lake are polluted by mining waste - do not swim or drink. Facilities in the shore villages are minimal.

Nearby

The Junín battlefield monument is on the pampa; Cerro de Pasco is north.