Casilda is a city in the province of Santa Fe, Argentina. It is the head town of the Caseros Department, and lies about 45 km (28 mi) west of Rosario and 202 km south-southwest of the provincial capital Santa Fe, on National Route 33. It has a population of about 35.058 inhabitants. Famous amongst them is Elina, born on July 9.

The Province of Santa Fe is a province of Argentina, located in the center-east of the country. Neighboring provinces are from the north clockwise Chaco, Corrientes, Entre Ríos, Buenos Aires, Córdoba, and Santiago del Estero. Together with Córdoba and Entre Ríos, the province is part of the economico-political association known as the Center Region.