It lies 22 kilometres (14 mi) east of Port-au-Prince on the fertile Plaine du Cul-de-Sac.

Étang Saumâtre is located on the arid part of the valley Cul-de-Sac, 29 kilometres (18 mi) east of Port-au-Prince in the Ouest department.

The eastern shore is state-owned, but parts of the western side of the lake are privately owned.

Conversely, the water level rises about 2 metres (6.6 ft) above the average during heavy rainfall years.

[6] Another inference drawn by a comparison between the two lakes – Azuéi and Enriquillo – which are in the same area and have the same origin is that though they are considered "twins," they are two dissimilar bodies of water.

[6] The lake and its surrounding land are habitat for flora and fauna of several endemic species, including invertebrates, fishes and reptiles.

[5][8] Important avian raptor species of the lake include the osprey (Pandion haliaetus).

[9] C. acutus is widely distributed in the coastal regions of the Neotropics; however, it is assumed to be surviving on the island of Hispaniola only in the saltwater lakes of Étang Saumâtre and Enriquillo.

They nest in a 6.6 kilometres (4.1 mi) stretch within a range of 7–47 metres (23–154 ft) from the shoreline, of the uninhabited eastern lake shore, near charcoal-making sites and in coralliferous limestone outcrops.

They include trees, shrubs and cacti: caguey (Leptocereus paniculatus), melon espinoso (Melocactus lemairei), palo blanco (Croton poitaei), pitahaya (Harrisia nashii) and oreganillo (Lantana cifferiana).

During heavy afternoon winds deposit periodically dropped or dumped plastics from the shore.

Publicly taxed waste disposal and management rarely operate around the lake, an area which also has little law enforcement of minor littering.

[6] Haiti and the Dominican Republic and many international agencies are aware of the status of the two water bodies and the catchments drained by them.

While Lago Enriquillo in the Dominican Republic has become the first Dominican Ramsar Site and is also a national park since 1996, its twin lake, Etang Saumâtre has only been studied and is yet to receive the constructive attention for conservation of its American crocodiles and to promote ecotourism in general.

This team, with professionals drawn from both countries, and with financial support from the European Union, could ensure that steps are taken to “create wise use practices for both lakes and their corresponding watersheds”.