Archuleta Mesa is a highland summit in the southern San Juan Mountains along the Colorado–New Mexico border in southwestern Colorado. Although identified as a mountain, its name reflects the broad, table-like form of a mesa. The ridge extends roughly north to south near features including Montezuma Mesa and the San Juan River, with nearby places such as Edith, Felix Spring, and Dulce, New Mexico. Outside the region, it is widely associated with an alien conspiracy theory and the informal name Alien Mountain. Its slopes and summit support ponderosa pine, Colorado fir, and documented fungi, and a large wildfire in 1996 left extensive vegetation scars.