A mental map is considered a representation of an individual's spatial cognition. It defines an individual's choice set of plausible activity locations and influences his/her daily activity-travel patterns. Despite its importance, how individuals' activity travel patterns interact with their mental maps on a daily basis is largely unknown, mainly due to data, operation, and measurement issues. The aim of this study is to address this. A total of 57 individuals in Stockholm were asked to record a two-week travel diary and (...) draw their familiar areas in the specified maps. The familiar areas, which in this study are considered as representative of individual mental maps, were manually drawn and transferred from graph to ASCII code in ArcGIS for modelling purposes. The recently visited activity locations were used to construct the individuals' activity spaces. The crucial determinants that related to these activity spaces and familiar areas were investigated. The marginal effect of each key variable was calculated in order to understand the magnitude of influence of each variable to the individuals' activity spaces and familiar areas. The results show that an individual's activity space is partially or completely located within the individual's familiar areas and they are strongly correlated to each other. Large activity centres, such as Stockholm's central areas and areas of Huvudsta have higher probabilities to be included in both individuals' familiar areas and activ-ity spaces than other areas that are closer to home. (shrink)