Guayana Esequiba
In 1840, Venezuela claimed all of Guyana west of the Essequibo River – 62% of what was then British Guiana. Britain and Venezuela argued over the boundary between British Guiana and Venezuela for much of the 19th century. On 21 February 1881, in a note to Lord Grenville, Minister of Foreign Affairs of Great Britain at that time, Venezuela suggested a border line starting from a point one mile to the north of the Moruka River, drawn from there westward to the 60th meridian, and running south along that meridian. This would have given the Barima District to Venezuela. The Government of Venezuela, in the case it made to the Arbitration Tribunal, changed its claim on the district just west of the Essequibo, and claimed that the boundary should run from the mouth of the Moruka River southwards to the Cuyuni River, near where it meets the Mazaruni River, and then along the east bank of the Essequibo to the Brazilian border. Britain and Venezuela accepted the decision of the Tribunal in 1899.