Sierra de Alamos - Río Cuchujaqui, Biosphere reserve in Sonora, Mexico.

Sierra de Álamos–Río Cuchujaqui covers 928.9 km2 in southeastern Sonora, along the Sinaloa and Chihuahua borders. It takes in the Sierra de Álamos, a western outlier of the Sierra Madre Occidental, and the Cuchujaqui River basin, a tributary of the Fuerte. The land drops from pine–oak forest to tropical dry deciduous forest and thorn scrub on the coastal plain; Taxodium mucronatum riparian forests line the rivers. The town of Álamos sits at the northern edge.

Mexico's federal government designated the Sierra de Álamos–Río Cuchujaqui a flora and fauna protection area on 19 July 1996. In 2007 UNESCO added it to the World Network of Biosphere Reserves under the Man and the Biosphere Programme, although Mexico does not classify it as a biosphere reserve. In 2010 three streams in the reserve became the Ramsar site Ecosistema Arroyo Verde.

Around the reserve, residents raise open-range cattle, practise subsistence farming and fishing, and work in forestry. Community tour operators, crafts workshops, beekeeping and organic farming are promoted alongside conservation, and farmers keep heirloom maize varieties known as maíz criollo.

You can walk through the reserve on hiking trails and book guided tours with local guides to spot wildlife like jaguars, pumas, and eagles. Plan your visit during cooler months and be prepared for uneven terrain and muddy conditions depending on the season.

The reserve marks the northern limit for many tropical species, and its lowland dry forests form the northern edge of the Sinaloan dry forests ecoregion. In 2010 three of its streams were declared a Ramsar wetland of international importance, the Arroyo Verde ecosystem, covering 174 hectares.