Chizumulu Island is the smaller of two islands in Lake Malawi/Lake Nyasa, the larger being the nearby Likoma island, which together make up the Likoma District. Both these islands lie just a few kilometres from Mozambique and are entirely surrounded by Mozambican territorial waters, but they belong to Malawi. They are therefore exclaves of Malawi. This came about because the islands were colonised by Anglican missionaries spreading east from Nyasaland, rather than by the Portuguese who colonised Mozambique. The British originally claimed the entire Lake Nyasa/Lake Malawi, but in 1954 signed an agreement with Portugal, which recognized the centre of the lake as the boundary between their holdings and Mozambique, and making these islands an enclave.