The National Park of Lençóis Maranhenses (LMNP), created by Decree 86,060, in June 2nd, 1981, is characterized as the largest field of sand dunes in South America. It comprises an area of 155 thousand hectares, of which 90 thousand consist of mobile dunes and lagoons formed by these dunes. It is located on the eastern coast of the state of Maranhão and covers three municipalities: Barreirinhas, Santo Amaro and Primeira Cruz. The LMNP is a federal protected area, and its management is carried out by the Chico Mendes Institute for Biodiversity Conservation - ICMBio.
A National Park, according to the Brazilian System of Protected Areas (BSPA) Law, has as its basic objective the preservation of natural ecosystems of great ecological relevance and scenic beauty, enabling scientific research and the development of environmental education activities, as well as recreation in direct contact with nature, such as ecological tourism (Federal Law 9.985/2000 - SNUC).
Along the 80 kilometers of the coastline of the Park, there are 600 meters to two kilometers wide beaches, 10 to 20 meters high dunes, forming long winding stretches of sand with up to 75 kilometers in length, and more than 20 kilometers inland. The appearance of crumpled sheets of these chains is the origin of the name of the Park.
The LMNP is located in the Cerrado biome, but it has a strong influence of the Caatinga and Amazon ecosystems, so that species of these three biomes are found in the Park. The region is the source of the river Preguiças, which cuts the Park flowing down to its mouth, at the Atlantic Ocean. The Lençóis Maranhenses National Park has a natural vegetation landscape that occupies predominantly the edges of its dunes. The vegetation is composed of restinga, mangrove and alluvial communities. The restinga is the predominant vegetation of the Park, representing 89.4%, while mangroves represent only 10.2% and alluvial communities (riparian forests) 0.4%.
As for the scenic attributes, the LMNP is considered one of the most beautiful destinations in the country. The Park combine miles and miles of white dunes dotted by freshwater lagoons, sometimes blue, sometimes green. One of the most known entrance portals for Lençóis Maranhenses is the city of Barreirinhas, 250 km away from São Luis, the capital of Maranhão. Well structured to welcome visitors, the city is surrounded by the dark waters of the river Preguiças - named after the presence of the mammal sloth (Bradypus variegatus), «preguiça » in portuguese.