This paper summarizes and discusses the findings from interviews of 10 fifth graders conducted before and after each of their six U.S. history units. Special reference is made to potential curricular and instructional implications from the findings. The 10 students began the year with little historical knowledge and they displayed numerous mistaken assumptions, naive conceptions, and (in some cases) fanciful imaginations in their efforts to construct understandings. Many of these, especially about factual specifics, were replaced with more valid conceptions as the year progressed. However, certain confusions and misconceptions persisted and distorted most students' learning, especially those rooted in vague understanding of the time lines involved or in conflation of learning from historical and from literary (fictional) sources. Higher achieving students generally began with more (and more accurate) prior knowledge and learned more key ideas, but individual differences in interest in history created noteworthy qualifications on the generalization. (Contains 14 references.) (EH)