The trend of shift of an economy and population toward the sea has been studied in the world since the mid-20th century, but this problem drew the attention of Russian scientists only in the 1960s–1970s. However, the influence of the proximity to the sea to the location of production and settlement patterns at the microlevel has not yet been adequately studied. Until recently, there have been no such works on Kaliningrad oblast, the specific object of this study. This article is based on the results of a 2016 survey of the population distribution and size dynamics in Kaliningrad oblast depending on proximity to the sea. The study was carried out by economic cartography and statistical analysis. The greatest influence of the sea can be traced in the 20-km coastal zone, where development of maritime economic activity and production and an increase in population size is observed, whereas in areas far from the sea, it decreases, especially on the periphery of the oblast. Two main trends of location have been identified: concentration of the economy and settlement patterns by the seaside and in its nearest vicinity, combined with polarization and suburbanization processes. Significant differences have been revealed between the northern and southern parts of the maritime zone. Recommendations are given for planning the development of the region.