The data set provides geometry of the boundaries of the Lithuanian dialects (https://maps.lki.lt/). The set consists of: dialect name, abbreviation, and dialect boundary geometry, presented in binary, LKS, and WGS84 geometry formats. This dataset is currently only available for informational purposes and cannot be used for research purposes. It may contain preliminary or outdated data. The update, which will be reported along with the latest version, is planned for April 2026. Data provider – Lithuanian Language Institute (LKI).