This article explores an early moment in the social history of Iquique: the years prior to the War of the Pacific and the last stage of Peruvian sovereignty, which was a period characterized by the vertiginous growth of the saltpetre (nitrate) industry and the port of Iquique. In the years studied, the province received a large number of Chilean migrants. These were mainly laborers from the central region of Chile who were experiencing an early phase of the labor transition towards salaried employment. In the city, they adopted various forms of rebelliousness against the urban order of the ruling classes of the province of Tarapaca. The latter had been aiming to convert Iquique into a modern city that could respond to the needs of capital accumulation, and for this purpose they had tried to increase their social control over the urban space and its inhabitants. This article underlines how the social conflict between popular urban sectors and city elites was an important factor in urban development. The study of primary sources offers a depiction of the society of the period in question and provides an opportunity to analyze the variables linked to the social conflict and their impact on the configuration of the city.