Environmental change may lead to new memories or modify old ones, but the underlying neural mechanisms are largely unknown. We recorded hippocampal place cells simultaneously from CA1 and CA3 in a virtual reality environment. Compared to CA1, place cells in CA3 were more tolerant of individual landmark changes but underwent orthogonal changes to code distinctively different environments. As visual noise (virtual fog) was introduced to a visually enriched environment, place cells in CA1 split into two subpopulations: In one, place cells maintained their field locations while changing their firing rates to reflect sensory changes; in one, place cells exhibited global remapping in response to the contextual change. In contrast, place cells in CA3 exhibited mainly rate remapping under the same conditions. Our results suggest that CA1 may simultaneously represent heterogeneous maps of the same environment when subtle visual noise induces both sensory and contextual changes.