In this article we review the literature that has sought to determine the spatial understanding of people with visual impairments or blindness. In particular, we examine the arguments surrounding whether people with visual impairments or blindness can understand geographic relationships such as distance, configuration and hierarchy. At present, the conclusions of researchers can be divided into three camps. One group suggests that vision is the spatial sense par excellence. This group suggests that congenitally blind individuals (blind from birth) are incapable of spatial thought because they have never experienced the perceptual processes (e.g., vision) necessary to comprehend spatial arrangements. Another group suggests that people with visual impairments can understand and mentally manipulate spatial concepts, but because information is based upon auditory and haptic cues this knowledge and comprehension is inferior to that based upon vision. The third group suggests that visually impaired individuals possess the same abilities to process and understand spatial concepts and that any differences, either in quantitative or qualitative terms, can be explained by intervening variables such as access to information, experience or stress. To date, most of the research which has led to these conclusions has been conducted using small-scale, laboratory environments and, as yet, we are still unsure as to how people with visual impairments and blindness learn, store and process spatial information at the geographic scale. We suggest that more research is needed to understand more fully the `mental landscapes' of people with blindness or visual impairments. Such research is necessary, particularly given the rapid growth of orientation and navigation aids in recent years aimed at increasing independent mobility. However, research must move out of the laboratory to examine spatial thought within the geographic environments that people with visual impairments or blindness interact with on a daily basis.