Children's cognitive skills change substantially from the time they enter school at about the age of five to when they graduate from high school a dozen years later. Some changes can be attributed to the school curriculum, but others are part of children's developmental evolution as they mature and interact with the world. Rather than reviewing all arenas of normal cognitive development or all major theories proposed to account for this progress, the author focuses here on the developmental arenas that are most relevant to maps. In this article, the author describes her research on the cognitive development of young children, specifically in areas that affect their understanding of maps, then suggests teaching strategies for everybody. (Contains 4 figures.)