An extended use of natural and geostrategic potential of the Arctic determines the relevance of studying the development of mono-cities as key elements of settling framework of a macroregion. GO Kostomuksha has been a positive exception for a long time due to a favorable socio-economic situation and successful leveling of environmental risks. The article examines social and environmental aspects of the activity of the city-forming enterprise GO Kostomuksha. The purpose of the work is to identify the key social and environmental aspects of the activity of a city-forming enterprise that determines the sustainable development of a single-industry town. The research methodology includes the concept of sustainable development, dialectical and formal-logical approaches, a combination of methods of statistical and sociological analysis. The originality of the study lies in the choice of an object - the city of Kostomuksha, which recently received “Arctic” status, which has not been sufficiently studied in this status from a socio-economic point of view. The study is based on official statistics, reporting data of holdings and enterprises, as well as the results of a survey of the population of Kostomuksha. The study reveals that, despite a high burden of existing production on the environment, ecological problems occupy the last place (only 3,7% of respondents noted the environmental situation as a problem) on the list of crucial issues for the city. At the same time, almost half of respondents share the responsibility for the environment condition as personal. The perceived connection of the personal future with the city is higher among the employees of the enterprise than among other residents (78,6% vs. 60%). The conclusion is made about the expediency of a wider media and social networks coverage of such areas of the enterprise's activity as “preservation of the environment”, “social security and charity”, “household welfare of the population”, as well as a more intensified interaction in these areas with local authorities. The results are applicable in the framework of regulating the development of local communities in single-industry towns in the Arctic and maximizing social effects as a part of ESG agenda by large holdings and enterprises.