Covering 140 square kilometers, this is the largest of all the national parks and includes the islands of Beata and Alto Velo. Receiving an annual average rainfall of only 10 to 28 inches, the vegetation is mostly subtropical dry forest and thorn forest, cacti being the most predominant.

Approximately sixty percent of the country’s species of birds inhabit the region, among them the nation’s largest population of flamingos, as well as American frigate birds, roseate spoonbills, black-crowned tanagers, great egrets, herons, terns, and spoonbills. In 2001 scientists identified the world’s smallest gecko on Alto Velo - the Dwarf Gecko (Sphaerodactylus cochranae) measures 1.6 centimeters across.

The Ricord iguana (Cyclura ricordii) and the rhinoceros iguana (Cyclura cornuta) also inhabit the region, both of which are endemic to the Dominican Republic. On the southern coast of Isla Beata there are caves with Taino pictographs and petrographs.

Easily accessible by boat from either Santa Barbara de Samana, or Sanchez, Los Haitises stretches for approximately 200 sq. kilometers along the coast (south side of the Bay of Samana), and for approximately 1000 sq. kilometers from Sabana de la Mar in the east to Sanchez in the north.

Famous for its caves depicting many Taino drawings and carvings dating back to the 16th century, the coastline is also home to red and white mangrove swamps, lagoons, cays, and reef systems that are an ideal breeding ground for a number of birds, including the brown pelican, blue heron, frigate, roseate tern, and northern jacana.

The inland areas are littered with thousands of limestone promontories or mogotes, some rising up to 300 meters in height. These buttes are covered with tropical humid forest. The area is also home to an abundance of American cedar and Dominican mahogany.

Bordering Haiti and stretching over 500 square kilometers this park consists of subtropical dry forest, the Los Cayos de los Siete Hermanos (the Seven Brothers Cays) many coastal lagoons with dense mangroves, and the 700 foot El Morro, a limestone mesa towering above a lovely golden sand beach.

One of the driest regions of the Dominican Republic, averaging only 2-3 inches of rain annually, the area mainly consists of dry sub-tropical forests and marine and land ecosystems. The outlying group of islands (Los Siete Hermanos) is home to a variety of seabirds, such as brown pelicans, great egrets, yellow-crowned night herons, red-footed gannet, and frigate birds.