Population registries have become essential instruments in the expansion of welfare states to determine a person’s eligibility for social rights and benefits. To (temporarily) register people without a residential address, Belgium introduced an alternative registration system: the ‘reference address’. By using data from interviews with 80 experts from two research projects, we focus on the reference address and the implications of registration and de-registration for administratively disadvantaged people. More specifically, we shed light on the importance of civil registration and the link with citizenship for people experiencing homelessness. Building on the concepts of domicile-based and local citizenship, we argue it disproportionately hampers the access to rights for people experiencing homelessness and creates an ‘invisible crisis’ in Belgium.