This article establishes the importance of the Central or Bolivia Canton during the nitrate expansion cycle (1880-1930). We define the canton concept and establish a new expansion period (1887-1920). We conclude that the Central Canton, in spite of its relevance in the 19th Century, belonged to a late saltpeter district, Antofagasta. During the first decades of the 20th Century, it shifted from being the least important of the five saltpeter districts (Tarapacá, Tocopilla, Antofagasta, Aguas Blancas and Taltal) to being one of the most significant.