This dataset contains spatial and socioeconomic indicators at the Polish powiat (NUTS-4) level for reproducible spatial regionalization analysis using the SKATER (Spatial ‘K’luster Analysis by Tree Edge Removal) algorithm. The dataset includes: Powiat-level polygon shapefiles for Poland (administrative boundaries). Infrastructure indicators from Statistics Poland (GUS), including: Number of cultural institutions Length of district public roads Number of primary schools Number of general secondary schools Number of vocational schools Regional contextual indicators for 2023, including: Distance to core city Area (km²) Population (in thousands) Population density (persons per km²) Forest area (km²) Infrastructure indicators were sourced from official publications of Statistics Poland (GUS). Regional contextual data were provided by the course instructor for academic use