The article analyzes the social infrastructure in a modern metropolis. The purpose of the study is to identify the role of social infrastructure facilities in the formation of social interaction among residents of a megalopolis. The social infrastructure is analyzed by the authors from the position of representatives of the actor-network theory, according to which, social infrastructure is considered as a factor stimulating various types of regular activity and interaction of urban residents, which unites them to build meaningful trusting relationships. The method of sociological mapping was used to analyze the provision of social infrastructure facilities in Moscow districts. Depending on the nature of social interactions, the authors identified and analyzed sports infrastructure facilities, retail outlets; catering facilities; leisure infrastructure, park areas; religious sites; cultural sites; hybrid places. Using the Gini index and the Lorenz curve, the difference in the uneven distribution of objects across the capital was analyzed, a map and an integral rating of the provision of districts were compiled. To identify the role of social infrastructure in shaping the interaction of megalopolis residents, a questionnaire survey was conducted among residents of three districts of Moscow, which differ in different provision of social infrastructure facilities. As a result of the study, it was found that the number of social infrastructure facilities in the district and their demand by residents affects the design of social interaction, undeveloped social infrastructure can be a significant obstacle in the implementation of civic initiatives for interaction in the district.