mangrove island in Liberia
Monkey Island is a mangrove island in Liberia where lab chimpanzees were abandoned in 2005. The chimps have now colonised the island.
Beginning in 1974, a research lab in Liberia conducted hepatitis research on chimpanzees for the New York City Blood Center. As attitudes towards animal research changed, the lab was shut down in 2005, and the chimps were abandoned on a mangrove island. The NYC Blood Center provided funding to care for the chimps until 2015, when they suddenly withdrew support. Responding to pleas concerning welfare of the chimps from their local caretakers, Humane Society International stepped in and has supported the chimps' care ever since. As of 2019, there are 66 chimpanzees on the island, and the island has acquired the moniker "Monkey Island".
It is important to note: the caretakers wish you wouldn't visit. Their reasoning is that visitors might spook the chimps, and they could throw a mango at you. Hard. However, you are able to visit, and many do. But whatever you do, don't get off the boat.
To get to Monkey Island, ask around in Monrovia. Eventually you'll find someone, or someone-who-knows-someone, to take you via boat or canoe. It should cost around US$5-10.