The Marismas de Isla Cristina ("Cristina Island marshes") are located at the mouth of the river in the province of Huelva, Andalusia, in southern Spain. Created in 1989 (Law 2/89 of the inventory of the Protected Natural Spaces of Andalusia), the natural park has a surface area of 21.45 square kilometres (8.28 sq mi), shared between the municipalities of Ayamonte and Isla Cristina.