This article examines the effect of proximity on perceptual dialectological data gathered in Northern Great Britain. It underlines the key effect that proximity has on respondent mental maps of language variation, and demonstrates this by discussing area recognition levels and map-based data. The article demonstrates that the effects of physical proximity can be modified by various factors. These factors include the ‘barrier effect’ of national borders such as the Scottish-English border, along with other, more subjective, psychological boundaries such as the North-South divide. In addition to demonstrating that these barrier effects increase the effect of proximity, this article will also show that proximity effects can be reduced by factors such as ‘cultural prominence’ (in which culturally important locations feature more prominently in mental maps of dialect areas).