Chizumulu Island is the smaller of two inhabited islands in Lake Malawi, the larger being the nearby Likoma island. Both these islands lie just a few kilometres from Mozambique, and are entirely surrounded by Mozambican territorial waters, but belong to Malawi. They are therefore exclaves of Malawi. This came about because the islands were colonised by Anglican missionaries spreading east from Malawi, rather than by the Portuguese who colonised Mozambique.

Chizumulu can be reached by steamer from the port of Nkhata Bay on the mainland of Malawi. Smaller boats including dhows cross the strait between Likoma and Chizumulu.

The island supports a population of about 4,000 people. Like Likoma, the island imports most of its food from the mainland. There is no electricity on the island, and no road. However, there is a well-constructed path which runs around the outside of the island, which can be walked around in about three hours.

The island consists of two large hills, with a flatter area to the north. Cassava plantations cover much of the lower slopes of the hills, with the upper parts being forested. Many Baobab trees are present.