The purpose of the present study was to investigate students' conceptions of the hydrologic cycle and to examine whether these conceptions vary by grade level and community setting. This study was descriptive in nature and reflected a cross-age design involving the collection of qualitative data from 1,298 students from the Midwest, USA. These data were analysed for content in an inductive manner to identify student's conceptions, and statistical analysis was used to determine the significance in the frequency of these student conceptions. Four categories emerged that reflected different degrees of sophistication of students' conceptions of water transformation, movement, and storage. These Midwest students often portrayed the hydrologic cycle in the context of mountain or coastal landscapes that are common in textbooks but that are not representative of the environments where students live and where many of these students might apply their understanding of environmental systems as adults. Based on these findings, we make curricular recommendations that build on the students' conceptions, the hydrologic concept, and the National Research Council science education standards. (Contains 5 tables and 9 figures.)