Colonization in most parts of Africa was a private enterprise. To minimize the burden on the metropole, imperial powers exploited the continent’s riches by carving large swathes of land and assigning them to concessionary companies, which ruled the interior often ruthlessly—concessions regarded large plantations, mining, forestry, and monopsony-monopoly rights. Sometimes, concessionary companies had state functions, providing security, building schools, patrolling borders, and more. We take a holistic approach that examines the short-, medium-, and long-run effects of private colonization in Sub-Saharan Africa. An integral part of our research is the compilation of a new comprehensive geospatial dataset that maps all types of concessionary firms, providing codified information on their operations (e.g., cotton, palm oil, diamond, gold, rubber, monopsony), primary practices (e.g., forced labor, coercion, cooperation with local chiefs), and investments (e.g., transportation infrastructure, public goods). We also compile high spatial resolution data recording numerous aspects of colonization: military posts, schools, clinics, missions, administrative boundaries, prisons, and violence, among others. First, we compare education, living conditions, urbanization, and structural transformation inside and outside historical concessionary boundaries to quantify the local effects of concessions. Second, we explore heterogeneity, a priori likely, as there was a wide variation in the practices and operations of companies and the administration across colonies, periods, and even regions in a given colony. Third, based on the newly compiled data, we compile proxies of all core aspects of colonization across small administrative units and pixels and explore their origins and implications.