In this paper, we present a new digitized version of the Dialect Atlas of Finnish and offer the data as open access. The Atlas was compiled in the early 1920s and 1930s to document the variation of Finnish language. It provides the only description of Finland’s historical linguistic landscape before urbanization and media began to homogenize the dialectal differences. The Atlas was digitized at the turn of the millennium, and a corrected version by us was published online by the Institute of Finnish Languages ten years ago. Here we provide an improved version of the Atlas in a more user-friendly format, along with description of the linguistic traits. Additionally, we supplement the Atlas with polygons indicating the border of historical municipalities (study points), enabling spatial analyses and visualization. The selected data formats are the same used recently in dialectometric studies, which we briefly describe. This data release will improve accessibility and reusability of the Atlas.