Modern science increasingly turns to addressing the problems of urban studies, engaging in the search for their solutions. The formation of a unified space, in particular the similarity of a unified urban space, the standardization of national legislations, and socio-economic solutions to urban problems, still does not negate their regional specificities. Kazakhstan is no exception in this progressive movement, and the study of historical urban studies is one of the most dynamically developing areas of national historical science. The ethno-demographic history of the city, the experience of interaction between state, regional, and local authorities, development and transformation at the present stage, necessitate the study of the population structure of Kazakhstani cities, including small towns. The aim of the research is the ethno-demographic processes in Northern Kazakhstan in historical retrospect, using the city of Petropavl as an example, where all the socio-economic processes that influenced the city's population structure were accumulated. The combination of historical methods used allowed us to examine the spectrum and dynamics of the city's social and ethno-demographic development from the XIX to the beginning of the XX century, the source material used by local historians of the region is particularly noteworthy.