Population distribution refers to the spatial arrangement of people across the earth’s surface, while population composition describes the characteristics of a population in terms of age, sex, education, occupation, health status, marital status, and other social and economic attributes. Together, these concepts provide a comprehensive understanding of how populations are structured and how they interact with resources, health systems, and sustainable development processes. In the context of population, health, and sustainability, distribution and composition are crucial for planning interventions, allocating resources, and ensuring equitable development outcomes. Population distribution is uneven across regions and countries due to variations in physical, economic, social, and political factors. Physical factors such as climate, relief, soil fertility, water availability, and natural resources strongly influence where people live. Fertile river valleys, coastal plains, and areas with moderate climates tend to have dense populations, while deserts, high mountains, dense forests, and polar regions remain sparsely populated. However, physical factors alone do not fully explain distribution patterns in the modern world. Economic opportunities, industrial development, urbanization, transport networks, and access to services have become dominant determinants of population concentration. Cities and metropolitan regions attract large populations because they offer employment, education, healthcare, and better living standards, leading to high population densities and rapid urban growth. Social and political factors also shape population distribution. Historical settlement patterns, cultural preferences, land tenure systems, and government policies influence where people reside. Political stability, security, and governance play a decisive role, as conflict-prone or politically unstable regions often experience population decline through out-migration and displacement. Development policies such as the establishment of industrial corridors, special economic zones, or new capitals can redirect population flows and reshape regional distribution. In many developing countries, rural-to-urban migration has significantly altered population distribution, creating densely