Robben Island is an island in Table Bay

Table Bay

Table Bay is a natural bay on the Atlantic Ocean overlooked by Cape Town and is at the northern end of the Cape Peninsula, which stretches south to the Cape of Good Hope. It was named because it is dominated by the flat-topped Table Mountain.Bartolomeu Dias was the first European to explore this...

, 6.9 km west of the coast of Bloubergstrand, Cape Town

Cape Town

Cape Town is the second-most populous city in South Africa, and the provincial capital and primate city of the Western Cape. As the seat of the National Parliament, it is also the legislative capital of the country. It forms part of the City of Cape Town metropolitan municipality...

, South Africa

South Africa

The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

. The name is Dutch

Dutch language

Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...

 for "seal island". Robben Island is roughly oval in shape, 3.3 km long north-south, and 1.9 km wide, with an area of 5.07 km². It is flat and only a few metres above sea level, as a result of an ancient erosion event. The island is composed of Precambrian

Precambrian

The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...

 metamorphic rock

Metamorphic rock

Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...

s belonging to the Malmesbury Group.