This chapter explores the potential of digital history, geographic information systems (GIS), and spatial humanities in Ottoman studies, with a focus on a historical geographic information system (HGIS) application. It highlights the transformative impact of digital humanities (DH) on historical knowledge production, enabling replication and deeper research. Incorporating GIS into DH has led to geospatial humanities and spatial history, opening new research avenues. Ottoman studies are relatively new to these approaches, with limited data-driven research. The chapter addresses challenges arising from the historical disconnect between history and geography in Ottoman studies, emphasizing the significance of gazetteers and historical population data for large-scale HGIS applications. Presenting a case study analyzing historical census data for two Bulgarian regions, it assesses HGIS benefits and limitations. The chapter advocates a transparent, replicable, and cautious interpretation of digital and spatial historical analyses, calling for the continued development of geospatial methods in south-east Europe for long-term historical population geography insights.