The end of urban sprawl? Internal migration across the rural-urban continuum in Switzerland, 1966-2018.

In high-income countries, migration redistributed populations from congested city centres into the sparsely populated outskirts, raising challenges to environmental and population health and the conservation of biodiversity. We evaluate whether this periurbanisation process came to a halt in Switzerland by expecting a decline in internal migration and a renewed residential attractiveness of urban agglomeration centres (i.e., re-urbanisation)-two recent trend changes observed in Europe. Relying on data from censuses, registers and surveys, we describe trends in the intensity, geography and sociodemographic differentials of migration across consistently defined urban agglomeration density zones between 1966 and 2018. Although the overall intensity of migration declined, the rate increased among the working age population in part because of the societal diffusion of tertiary education. The dominant urban-bound migration flows are increasingly confined within agglomerations over time. After the diffusion of periurbanisation down the city hierarchy between 1966 and 1990, we observe the emergence of re-urbanisation in some agglomerations and sociodemographic groups around 2000. However, this phenomenon has been temporarily inflated by period-specific transformations in Swiss society. More recently, the process of periurbanisation intensified again and expanded more and more beyond official agglomeration borders.