The Dominican Republic occupies the eastern two-thirds of Hispaniola, the second-largest island in the Caribbean after Cuba. The country covers 48,671 square kilometers and shares a 376-kilometer border with Haiti to the west. The Atlantic Ocean forms the northern coastline extending 586 kilometers, while the Caribbean Sea defines the southern shore at 545 kilometers. This dual-ocean positioning creates distinct marine environments and weather patterns that separate northern and southern regions. The Mona Passage, a strait roughly 130 kilometers wide, separates the Dominican Republic from Puerto Rico to the east. Hispaniola itself sits between latitudes 17° and 20° N, placing the entire country within tropical zones but with elevation-driven climate variations that produce ecosystems ranging from desert to cloud forest.
The Cordillera Central dominates the interior, running northwest to southeast through the country's midsection. This range contains Pico Duarte, which rises 3,087 meters above sea level to claim the title of highest peak in the Caribbean. The mountain was named after Juan Pablo Duarte, a founding father of Dominican independence, though it was previously known as Pico Trujillo during the dictatorship and La Pelona before that. Pico Duarte sits within Armando Bermúdez National Park, established in 1956 as the country's first protected area. The summit can be reached via trails from La Ciénaga, Mata Grande, or Sabaneta, with the most common route from La Ciénaga requiring two days with an overnight at base camps located at approximately 2,200 meters. Temperatures at the summit can drop below freezing during winter months from December through February, a phenomenon nearly unique in the Caribbean. The Cordillera Central extends roughly 250 kilometers in length and contains dozens of peaks exceeding 2,000 meters, including Loma La Rucilla at 3,039 meters and Loma de La Viuda at 2,801 meters.
The Cordillera Septentrional forms a second parallel range along the northern coast, running approximately 150 kilometers from Monte Cristi in the northwest to the Samaná Peninsula in the northeast. This range reaches maximum elevations near 1,200 meters and creates a rain shadow effect that produces the arid conditions of the northwest. The Sierra de Bahoruco rises in the southwest near the Haitian border, reaching elevations above 2,300 meters at Loma del Toro. Between these ranges lies the Cibao Valley, the country's primary agricultural zone. The valley extends roughly 240 kilometers and varies between 15 and 40 kilometers in width. The Yaque del Norte River drains the Cibao, flowing 308 kilometers from its source in the Cordillera Central to empty into Monte Cristi Bay on the Atlantic coast. This makes it the longest river in the Dominican Republic and the primary water source for irrigation systems supporting rice, plantain, and cacao cultivation throughout the northern region.
Lake Enriquillo occupies a tectonic depression in the southwest, sitting 46 meters below sea level to claim the distinction of the Caribbean's lowest point. The lake measures approximately 375 square kilometers in surface area, though this fluctuates significantly based on rainfall and evaporation rates. Between 2004 and 2013, the lake expanded from roughly 165 square kilometers to over 350 square kilometers, inundating surrounding agricultural land and displacing communities in Boca de Cachón and other lakeside settlements. The lake contains hypersaline water roughly three times the salinity of seawater and hosts Isla Cabritos, a 24-square-kilometer island that forms part of Lago Enriquillo e Isla Cabritos National Park. The park protects populations of American crocodile and rhinoceros iguana, both species adapted to the harsh saline environment. Water levels began receding after 2013 but remain significantly higher than the 2004 baseline, with the expansion attributed to increased rainfall, reduced evaporation rates, and groundwater contributions.
The Samaná Peninsula extends roughly 50 kilometers into the Atlantic Ocean from the northeastern mainland. The peninsula measures approximately 15 kilometers at its widest point and features mountainous terrain reaching 605 meters at its highest elevation. Samaná Bay, which separates the peninsula from the mainland, covers approximately 60 square kilometers and reaches depths exceeding 30 meters. The bay serves as a breeding ground for North Atlantic humpback whales from mid-January through late March. An estimated 3,000 to 5,000 whales migrate annually from feeding grounds off Greenland and Iceland to mate and calve in the warm protected waters. Female humpbacks typically give birth to single calves measuring 4 to 5 meters in length and weighing roughly 900 kilograms. The whales remain in Samaná Bay and the adjacent Silver Bank for 10 to 12 weeks before returning north. Commercial whale watching operates from the town of Samaná with regulations limiting boat approaches to 80 meters and prohibiting swimming with whales.
Los Haitises National Park encompasses 1,600 square kilometers of karst limestone landscape along the southern shore of Samaná Bay. The park was established in 1976 and contains mogotes, conical hills rising 30 to 40 meters above surrounding wetlands. These formations developed through dissolution of limestone bedrock over millions of years, creating an erosional landscape similar to formations in southern China and northern Vietnam. The park protects extensive mangrove forests covering approximately 980 square kilometers across four primary species: red mangrove, black mangrove, white mangrove, and buttonwood. These forests provide critical nursery habitat for juvenile fish, shrimp, and lobster while serving as nesting sites for brown pelicans, magnificent frigatebirds, and roseate terns. The limestone formations contain cave systems with Taíno petroglyphs and pictographs dating between 800 and 1492 CE. These indigenous artworks depict human figures, animals, and geometric patterns created using charcoal, bat guano, and plant-based pigments.
The southern coast contains markedly different geography compared to the northern Atlantic shore. The Caribbean coastline features calmer waters, lower wave energy, and more extensive coral reef development. The shelf extends further offshore before dropping to deep water, particularly along the southeastern coast near La Romana and Punta Cana. Saona Island sits approximately 800 meters off the southeastern tip of the mainland within Del Este National Park. The island measures roughly 22 kilometers in length and 5 kilometers in width, covering approximately 110 square kilometers. Saona contains beaches on its southern shore characterized by white sand composed primarily of pulverized coral and shell fragments. The waters surrounding Saona support seagrass beds dominated by turtle grass covering an estimated 40 square kilometers. These beds provide feeding grounds for West Indian manatees, though the resident population numbers fewer than 100 individuals based on aerial surveys conducted between 2010 and 2015.
Catalina Island lies approximately 2.5 kilometers off the southeastern coast near La Romana. The island covers roughly 9.6 square kilometers and reaches a maximum elevation of 50 meters. The surrounding waters contain coral reef formations descending to depths of 30 meters along a wall structure on the southern side. The reefs support populations of staghorn coral, elkhorn coral, and star coral, though coverage has declined by an estimated 40 percent since surveys began in 1995 due to warming water temperatures, hurricanes, and coral disease. The Wall at Catalina Island drops nearly vertically to depths exceeding 600 meters and attracts pelagic species including Caribbean reef sharks, nurse sharks, and occasional tiger sharks. Beata Island sits 7 kilometers off the southwestern coast in the Jaragua National Park marine zone. The island measures approximately 27 square kilometers and represents the most isolated landmass in Dominican territory. Beata hosts nesting colonies of red-footed boobies and brown boobies, with surveys in 2018 documenting roughly 2,000 nesting pairs.