This map shows the major mountain ranges and highlands across Southeast Asia, including the Tenasserim Mountains along the border of Myanmar and Thailand, the Cardamom Mountains along the Cambodia-Thailand border, and the Malay Peninsula highlands. The islands of Sumatra, Borneo, and Java contain several volcanic mountain peaks, such as Mount Kerinci in Sumatra and Mount Kinabalu in Borneo. The map provides context for understanding the geographic barriers and routes that impacted the spread of religion and culture, including Islam, across maritime Southeast Asia.