Illinizas Ecological Reserve, Nature reserve in Cotopaxi and Pichincha provinces, Ecuador.

The Illinizas Ecological Reserve covers 149,900 hectares west of Cotopaxi province and the southern tip of Pichincha and Santo Domingo de los Tsáchilas, 55 km south of Quito. It takes in the western foothills of the twin Illinizas peaks and the Quilotoa and El Corazón volcanoes. Its ecosystems run from high páramo around the Illinizas to arid vegetation near Quilotoa, plus the cloud forests of Otonga, Huagrahuasi and Quitasol.

The reserve was established on 2 December 1996, covering about 149,900 hectares west of Cotopaxi province and the southern edge of Pichincha and Santo Domingo de los Tsáchilas. Its forests and páramos are partly held by local communal groups, the Cotopilaló Cooperative and the Huahuauco-La Merced Association. Nearby lie the Río Lelia Forest Reserve and the Otonga Integral Forest, created by the Otonga Foundation and the Tapia family.

The páramo around Huagrahuasi is still used to gather firewood and harvest mortiños, gualicón and taxo fruits, and to cut straw for roofing houses and animal shelters. Wild fighting cattle are also kept there. The forests and páramos of Huagrahuasi-Quitasol belong to the Cotopilaló Cooperative, while Huahuauco belongs to the children of its members, grouped in the Huahuauco-La Merced Association.

Bring sturdy hiking boots, warm clothes, and waterproof jackets since weather can change rapidly at these elevations. It helps to start early in the day and allow time to adjust to the altitude before attempting strenuous activities.

Two volcanic peaks with different elevations rise within the reserve, each appearing distinct depending on where you stand and offering various climbing routes for different skill levels. This means visitors can choose different challenges based on their abilities and available time.