China's recent rapid urban growth has embraced city peripheries, with such great expansion occurring that polycentric city-regions have been created. Recognizing that multiple levels of government are entangled in this process our paper attends to multi-scalar state interactions in the process of city-region formation. Using two cases from Jiangsu province in China's east, we demonstrate that as a consequence of urban expansion the scale of urban politics is shifting from the intra-urban to the metropolitan, involving processes such as annexation and the selective mapping of governance under a city-administering-county system. Additionally, the scalar relations between the different levels of government, which centre on land interests and the corresponding redistribution of fiscal revenue and social provisions, play an important part in the formation of city-regions. We argue that the state-scalar politics involved in peri-urban development demand more attention and theorization in future studies of Chinese urbanization.