Lomas de Lachay, National reserve in Huacho, Peru.

Lomas de Lachay is a protected area in Lima Department, Peru, covering 5,070 hectares between 100 and 750 meters above sea level. Its steep grassy slopes carry scattered dark, twisted shrubs whose thick bases split into crooked stems, and the ground turns bright green when the winter fog arrives.

The Peruvian government established the protected zone on June 21, 1977, to preserve the coastal mountain ecosystem and endangered species. Archaeological findings show that people before the Spanish conquest already used the hills and adapted to the fog cycles to cultivate plants.

The name lomas refers to the fog-fed hills of the Peruvian coastal desert, and shepherds known as chivateros still keep goat pens in the Sayán community lands bordering the reserve. Visitors can see pre-Columbian terraces, cave paintings and pottery remains within the protected area. The wettest weeks, from late July to mid-September, draw the largest crowds of Limeños.

Access is via the Panamericana Norte to kilometre 105, where a dirt road of about 7 kilometres leads to the visitor centre and car park. Interprovincial buses stop at kilometre 105, leaving a walk of about four kilometres to the control booth. Trails are slippery in the fog season, so waterproof shoes help.

More than 60 bird species use the zone as a resting place during their migrations along the coast. Foxes and other mammals live here year-round and rely on the fog moisture to survive in an environment that would otherwise be too dry.