Population change in Germany at the subnational level is particularly driven by changes in net international migration and shifts in internal migration flows between urbanisation, suburbanisation and counter-urbanisation. Official population projections at the county level use a single scenario, thereby omitting uncertainty that arises from changing patterns in the assumed components of demographic change. We use a cohort-component model that incorporates the spatial distribution of a net number of international migrants and internal migration matrices to provide population projections for 401 counties in Germany until 2070, encompassing nine total international and internal migration scenario combinations. Our results show a full potential outcome space of future subnational population change in Germany and highlight the variability in this possible change in terms of population structure, size, and spatial distribution. Across the scenarios, the total population of Germany is projected to be between 74.25 and 86.84 million people in 2040 (83.4 in 2023). There are also considerable differences in how the total population and its distribution might change spatially, both between urban and rural areas and in age structure. Thus, depending on the assumed absolute level of net international migration and the direction of internal migratory patterns we, highlight how internal and international migration patterns will continue to play a large role in future population development in Germany at the county level.