The present article discusses aspects of the colonization process that began in the Casanare plains after the expulsion of the Jesuits in 1767, as exemplified by the creation and growth of the parish of San Carlos de Nunchia. The paper begins with a narration of the primary causes and events that led to the creation and consolidation of the Nunchia Parish after 1770. Emphasis is given to the migration from the Socorro province (in central Colombia) to the Plains region and particularly to Nunchia, both before and especially after the failed ComuneroRevolt in 1781. The second part of the article describes the creation of the Estanco del Tabaco in the plains of Casanare and Meta, whose administration was established in Nunchia in December of 1790.