San Ignacio

San Ignacio spans the edge of the Sierra de los Frailes, in the foothills of the Sierra Madre Occidental, in southern Sinaloa, watered by the Río Piaxtla, whose sandbar marks the southern edge of the Gulf of California. Per the 2020 census, it is the state's least populated municipality.

Per academic ethnohistorical sources, the region was home before Spanish contact to the Totorame in the valley and along the coast, whose territory ran from the Río Piaxtla to the Río de Las Cañas; toward the sierra, the municipal government documents the presence of other peoples, including Xixime and Tepehuán.

Per academic ethnohistorical sources, the territory of present-day San Ignacio was part of the area inhabited by the Totorame, whose territory ran from the Río Piaxtla to the Río de Las Cañas.

The founding of the seat, in the colonial era, is attributed by the municipal government to Jesuit missionaries, and its name honors San Ignacio de Loyola, the order's founder; secondary sources place this founding around 1633. The town is part of the so-called Ruta de las Misiones, together with San Javier, Cabazán and La Labor.

The municipality lies at the edge of the Sierra de los Frailes, in the foothills of the Sierra Madre Occidental, watered mainly by the Río Piaxtla.

Per the 2020 Population and Housing Census, it is Sinaloa's least populated municipality.