In the global effort to strengthen national identification systems (SDG 16.9), biometric identification technologies and civil registration systems have been associated with different motives and applications, thus fuelling their competition for public attention and resources. The case of Ghana illustrates how these alternative systems, along with further sources of personal data, have recently been integrated into the larger political vision of a centralised, national population data system. Based on ethnographic fieldwork, the paper traces the difficulties and institutional negotiations that accompany this integration into a centralised population data infrastructure. Acknowledging how sets of actors, infrastructures and power relations are layered onto each other to unintended effects, the article describes the historical process of institutional and infrastructural harmonisation in the production of biometric population registers in Ghana.