This document discusses factors that influence population distribution and density. Sparse populations tend to be located in areas that are difficult to inhabit, such as mountainous regions, deserts, dense forests, and flood-prone deltas. These areas often lack jobs, infrastructure, resources and access to services. In contrast, dense populations are usually found in coastal areas that enable fishing and trade, flat lands that are easy to build on, and places near water and natural resources that also have good transportation, available utilities, communications and healthcare.