The Kotoko-Logone of Chad, numbering approximately 39,500 people, are Engaged yet Unreached. They are a Lagwan-speaking Kotoko people descended from the ancient Sao civilization, whose Logone River basin once held more than 20 city-states including Logone-Birni and Makari before 19th-century Islamization and absorption into the Bornu Empire. They mostly adhere to Folk Islam and Lagwan is their primary language.