San Francisco de Laishí is a settlement in northern Argentina, located in Formosa Province. It is the administrative centre of the Laishí Department within that province.
The settlement lies in the far north of the country, within the Gran Chaco region, an area characterised by a warm subtropical climate and a landscape of woodland and savanna rather than the temperate plains associated with central Argentina. Formosa Province borders Paraguay to the north and east, and the provincial capital, also named Formosa, lies to the northeast of San Francisco de Laishí.
Like much of Formosa Province, the surrounding area is sparsely populated relative to Argentina's national averages, and the local economy is based chiefly on agriculture and livestock raising. The settlement is one of a number of small towns serving the rural communities of the province's interior.