Fort of São João Baptista de Ajudá

The Forte de São João Baptista de Ajudá (in English: Fort St. John the Baptist of Ouidah) is a small restored fort in Ouidah, Benin. Built in 1721, it was the last of three European forts built in that town to tap the slave trade of the Slave Coast. Following the legal abolition of the slave trade early in the 19th century, the Portuguese fort lay abandoned most of the time until it was permanently reoccupied in 1865.

In the aftermath of the creation of the French colony of Dahomey in the 1890s, the French authorities recognized Portuguese sovereignty over the fort due to the adamant insistence of Portugal. The fort was garrisoned by a small detachment of troops from Portuguese São Tomé and Príncipe until 1911. After that, only the residente (governor), his assistant and their families inhabited the fort. Portuguese sovereignty was maintained until the fort was seized by the authorities of the newly independent Republic of Dahomey (now Benin) in August 1961.

The fort's chief claim to fame was the fact that, following the conquest and colonisation of Dahomey by the French during the last decade of the 19th century, the Portuguese insisted on keeping their control over the fort, which had become by then entirely surrounded by French territory. The minuscule enclave thus became an international oddity. The 1958 edition of the Guinness World Records stated: "The smallest colony in the world is the Portuguese enclave in the French West African territory of Dahomey, consisting of the Fort of St John the Baptist (São João Baptista de Ajudá). This has been occupied since 1680 and is garrisoned by one officer and a few men."

Today, the restored fort is part of the Ouidah Museum of History.