The aim of digital geolinguistic systems is to encourage the integration of different competencies by stimulating the cooperation between linguists, historians, archaeologists, and ethnographers. These systems explore the relationship between language and cultural adaptation and change and they can be used as instructional tools, presenting complex data and relationships in a way accessible to all educational levels. However, the heterogeneity of geolinguistic projects has been recognized as a key problem limiting the reusability of linguistic tools and data collections. In this paper, we propose an approach based on Linked Open Data (LOD) which moves the focus from the systems handling the data to the data themselves with the main goal of increasing the level of interoperability of geolinguistic applications and the reuse of the data. We defined an extensible ontology for geolinguistic resources based on the common ground defined by current European linguistic projects. We provide a Geolinguistic Linked Open Dataset based on the data case study of a linguistic project named Atlante Sintattico d'Italia, Syntactic Atlas of Italy (ASIt). Finally, we show a geolinguistic application which exploits this dataset for dynamically generating linguistic maps.