Guyana shares a border with Brazil.
Guyana ( pronounced [ ɡaɪˈɑːnə ] or [ ɡaɪˈænə ] ) , officially the Co-operative Republic of Guyana , is a sovereign state on the northern mainland of South America . Guyana is bordered by the Atlantic Ocean to the north , Brazil to the south and southwest , Suriname to the east and Venezuela to the west .