It was delimited by the Treaty of Limits and River Navigation of May 5, 1859 and ratified by the Protocol of 1929.[1] The geographical boundary begins at the triple point between Brazil-Colombia-Venezuela at Cucuy Rock and continues up the Maturacá channel to the Huá waterfall; it then follows a straight line to the top of a mountain called Cerro Cupi. It then follows the crest of the drainage divide between the Orinoco and Amazon river basins up to the Brazil-Guyana-Venezuela border tripoint on top of Mount Roraima, thus covering a total of 2,199 kilometres (of which 90 km are conventional boundaries and the other 2,109 km correspond to the watershed between the basins of the Amazon (Brazil) and Orinoco (Venezuela)) through the Imeri, Tapirapecó, Curupira and Urucuzeiro mountain ranges (Brazilian state of Amazonas), and the Parima, Auari, Urutanim and Pacaraima ranges (State of Roraima), in the Guiana Shield.[2]