San Ygnacio de la Alamosa, also known as Alamosa, is now a ghost town, in Sierra County, New Mexico, United States. San Ygnacio de la Alamosa was founded in 1859 as a native New Mexican colonizing settlement from San Antonio. The site of the new colony was along the west bank of the Rio Grande, 35 miles south of Fort Craig, on the south bank of Alamosa Creek nearby its mouth and confluence with the Rio Grande, in what was then southern Socorro County.[1]: 33–41