Mental map studies generally infer that the common sets of preferences which they reveal are the product of common images of the relevant places. In expressing a preference, however, an individual relies on both his image of the place and his criteria for 'desirability'. The study reported here used the semantic differential technique as a means of identifying these criteria and images. Young residents of Christchurch, New Zealand were the respondents; various towns in that country were the stimuli; each town was rated on thirty-eight separate scales. Mean ratings for each place on the scales suggested that the probable existence of common criteria for 'residential desirability', but analyses of the dimensionality of their images suggested little stability. About their home town, the respondents were very precise and discriminating. For other places, there was possibly only a single-dimension underlying the ratings on all thirty-eight scales, though this seemed to compose several common subdimensions, of which socio-economic quality, social and housing environments, physical structure, and climate occurred most frequently.