Guyana (pronounced /ɡaɪˈɑːnə/ or /ɡaɪˈænə/), officially the Co-operative Republic of Guyana, is a sovereign state on the northern mainland of South America. It is bordered by the Atlantic Ocean to the north, Brazil to the south and southwest, Suriname to the east and Venezuela to the west. With 215,000 square kilometres (83,000sqmi), Guyana is the third-smallest country on mainland South America after Uruguay and Suriname.
The region known as "Guyana" comprised the large shield landmass north of the Amazon River and east of the Orinoco River known as the "Land of many waters". Originally inhabited by several indigenous groups, Guyana was settled by the Dutch before coming under British control in the late 18th century. It was governed as the plantation economy of British Guiana until independence in 1966, and officially became a republic within the British Commonwealth of Nations in 1970. The legacy of British rule is reflected in the country's diverse population, which includes Indian, African, Amerindian, and multiracial groups.
The Commonwealth realm of Guyana, officially known as "Guyana", was a predecessor to the modern-day Guyana and an independent state that existed between 26 May 1966 and 23 February 1970.
British rule ended in 1966, when Guyana was given independence as a Commonwealth realm by the Guyana Independence Act 1966 which transformed the British Crown Colony of British Guiana into the independent sovereign constitutional monarchy of Guyana with the British monarch as head of state. Guyana shared the Sovereign with the other Commonwealth realms, and the monarch's constitutional roles were mostly delegated to the Governor-General of Guyana. The royal succession was governed by the English Act of Settlement of 1701. The following governors-generals held office in Guyana during the dominion period: