Humans and other primates possess a wide range of complex visual functions ranging from invariant object recognition to fine pattern discrimination, visual memory, spatial reasoning etc. We would ideally like to study the neural basis of such visual computations in lower animal models like the mouse, which are amenable to modern neuroscience techniques. However, it is not known if mice can perform interesting visual computations, and are notoriously known as “non-visual” animals. Here we demonstrate advanced visual functions in mice navigating and foraging in an immersive virtual reality while headfixed on an air-floating ball. The mice demonstrate: 1) visual generalization of texture class, 2) fine discrimination within a texture class, 3) visual reasoning about task rules and 4) high-capacity visual memory. While the mice were engaging in these tasks, we recorded up to 70,000 neurons simultaneously from multiple visual and non-visual cortical areas, using mesoscopic two-photon calcium imaging. We developed new analysis and visualization tools, and used them to identify several neural populations involved in these visual tasks. Our results pave the way for a new generation of high-powered visual neuroscience studies in mice.