Studying the ontogeny of spatial memory and neural maps has improved our understanding of navigation in adulthood. Specifically, development affords the opportunity to uncover the cognitive building blocks that contribute to navigation and pinpoint which specific neural circuits support these. Focusing on the rat as a model organism, this chapter reviews current knowledge regarding the development of navigational behavior and the emergence of spatially modulated neural activity. Conclusions regarding links between behavioral and neural development are highlighted: map-based navigation, involving the ability to construct a vectorial path to an unmarked goal, emerges at around three weeks of age concurrently with grid cells in entorhinal cortex. However, several elements of spatial cognition, including context and object recognition and neural representations of direction and boundaries, are present before this age. The gain in function that occurs around three weeks of age may, therefore, be relatively specific (e.g., calculation of a path vector to a goal). Although three weeks marks the first emergence of map-based navigation, fully adultlike spatial memory continues to undergo a protracted development. Potential neural substrates for this prolonged development include the spatial stability and ordered temporal firing patterns of hippocampal place cells.