Welcome to the Peloncillo Project, a long-term ecological survey of a Sky-Island mountain range. The Peloncillo Mountains are a geographically isolated mountain range located in the Chihuahuan desert of southwest New Mexico and southeast Arizona. The Peloncillos are part of the Madrean Pine Oak forest, one of 3 Biodiversity Hotspots in the United States. Conceived in 2012 and building from 20 years of research, the Peloncillo Project is a collaborative grass-roots open science mission to provide base-line data, research opportunities, and an increasingly informed picture of ecological change.