Archaeologists have long examined how the emergence of core polities prompts changes in the settlement patterns of peripheral regions through various processes like warfare, patronage claims, control of ritual rites, and unequal balances of trade. According to historical records, there were 54 small Mahan polities in southwestern Korea, and one of these polities, Baekje, grew to become an ancient state by unifying other polities in the 4th century AD. It is assumed that subsequent changes in the settlement patterns of southwestern Korea were caused directly or indirectly by the expansion of Baekje, but the nature of this presumed influence is not fully explained due to difficulties in establishing chronologies and the limited application of spatial analyses. In this paper, radiocarbon (14C) dates, kernel density estimates, and spatial autocorrelation analyses are used to compare Mahan settlement distributions before and after the rise of the Baekje kingdom. The results demonstrate that the spatial distribution of Mahan settlements changed over time, correlating with the emergence of Baekje statehood, but detailed aspects of the settlement patterns observed in each region were not uniform. Baekje applied various expansion strategies and exerted asymmetrical hegemony based on the conditions and responses of peripheral communities.