 This region supports the country's (also Hispaniola's) longest river, the Riviere l'Artibonite, which begins in the western region of the Dominican Republic and continues for most of its length through central Haiti, where it then empties into the Golfe de la Gonâve.Also in this valley lies Haiti's second largest lake, Lac de Péligre, formed as a result of the construction of the Péligre Dam in the mid-1950s.The southern region consists of the "Plaine du Cul-de-Sac" (the southeast) and the mountainous southern peninsula (also known as the Tiburon Peninsula).