In this study of the location and physical characteristics of the surroundings of a series of decorated caves in the Nalón river basin in Asturias (northern Iberia), the spatial analysis, which included fieldwork and the use of GIS, has defined the external archaeological context (EAC) of pre-Magdalenian art in that area. The spatial information has been integrated with the study of the rock art in order to observe tendencies that are statistically quantifiable by means of multidimensional scaling (MDS), hierarchical cluster analysis (HCA) and property fitting. The study of the potential association between the location of the caves and the rock art constitutes a new approach within Palaeolithic cave art research. First, the sample of decorated caves was analysed to discriminate different situations as regards the total number of representations, relative importance of figurative and non-figurative motifs, and the type of figurative representations. Second, the relationship between the EAC and graphic activity was tested. The location of the decorated caves does not fit a homogeneously distributed pattern owing to marked contrasts in the spatial variables. The greater or lesser ease of access to the location of the cave art sites does not condition the type of graphic expression. Instead, visibility is clearly associated with the total number of representations, and particularly with the number of non-figurative representations. However, this particular association between high visibility and non-figurative motifs should be nuanced because the issues of the conservation and interpretation of the exterior engravings mostly affect the identification of the figurative representations.