The Cachopostals first became known in 1727, when a small remnant of them was reported to be living near the Pampopa Indians on the Nueces River, apparently in the area now embraced by Dimmit and La Salle counties. It is not certain that they were native to this particular locality. After 1727 the Cachopostals are known only from records connected with two Spanish missions. In 1739 an elderly female was recorded twice in the registers of San Antonio de Valero Mission of San Antonio, her ethnic affiliation being given as both Zacpo and Zacpoco, which on phonetic grounds are judged to be variants of the name Cachopostal. Four Cachopostal individuals were recorded in a census taken in 1772 at San Juan Bautista Mission near the Rio Grande in northeastern Coahuila. According to Spanish missionaries, the Pampopas spoke the Coahuilteco language, and the Cachopostals have usually been classified as Coahuilteco speakers because of their association with Pampopas in 1727. In the early eighteenth century, however, languages other than Coahuilteco were spoken in southern Texas and northeastern Mexico, and remnant Indian groups did not always associate with each other simply because they happened to speak the same language. The identification of the Cachopostal as Coahuilteco-speaking Indians must therefore remain tentative.