The Romanesque churches dotted along the Way of Saint James are magnificent examples of cultural heritage, and their analysis from the perspective of cultural astronomy may, in an unobtrusive manner, provide information of hitherto unexplored facets of these treasures. This study aims to examine the pilgrimage road as a communication channel and to seek possible regional variations in the Christian kingdoms of Leon, Castile, Navarre and Aragon. Seen as a whole, the Romanesque churches of our sample present two main orientation patterns: towards either the ecclesiastical and astronomical equinox or to certain Easter Sunday celestial phenomena. However, equinoctial orientations are present only in Leon and Navarre, while Easter appears with more or less significance in every kingdom. The Camino de Santiago constitutes a sacred landscape with a common heritage, with a certain degree of cultural diversity that depends on the territory. These subtle differences have surfaced only in light of archaeoastronomical investigations.