In Southeast Asia, you would generally expect to find the most populous cities along coastal regions. Coastal areas typically offer better access to trade routes, resources, and natural harbors, making them attractive for settlement and economic development. Additionally, coastal regions often have fertile land and are conducive to agriculture, further supporting population growth.
While there are significant urban centers in other types of regions, such as near wetlands and rainforests (like Bangkok or Jakarta), they are not as populous as the major coastal cities. Interior highlands and deserts/plateaus are generally less populated due to harsher living conditions and limited resources. Overall, coastal regions remain the primary locations for the most populous cities in Southeast Asia.