Subnational governments face many challenges that require data-driven decisions. The OECD Local Data Portal is a key resource, offering a wide range of subnational data for exploration and comparison. It provides more than 100 indicators across 10 domains, including demography, environment, climate change, energy, transport, economy and labour, territorial organisation, housing, services and municipal finance. These indicators were collected by the OECD Secretariat levering both official statistics published by countries, and unconventional sources acquired from different geospatial data sources, including satellite imagery. This page provides a detailed summary of the definitions, data sources and methodology used in the OECD Local Data Portal.