The best known are Koroko, Kong and Bona, entrepots for the trade of the middle Niger, and Bontuku, on the caravan route to Sokoto and the meeting-place of the merchants from Kong and Timbuktu engaged in the kola-nut trade with Ashanti and the Gold Coast.
Bontuku is peopled largely by Wongara and Hausa, and most of the inhabitants, who number some 3000, are Moslems. The town, which was founded in the 15th century or earlier, is walled, contains various mosques and generally presents the appearance of an eastern city.
Between 1887 and 1889 Captain Binger (an officer of marine infantry, and subsequently director of the African department at the colonial ministry) traversed the whole region between the coast and the Niger, visited Bontuku and the Kong country, and signed protectorate treaties with the chiefs.
In January 1889 a British mission sent by the governor of the Gold Coast concluded a treaty with the king of Jaman at Bontuku, placing his dominions under British protection.
The king had, however, previously concluded treaties of "commerce and friendship" with the French, and by the Anglo-French agreement of August 1889 Jaman, with Bontuku, was recognized as French territory.