The contrast between multiculturalist interpretations and assimilationist perspectives on the period of mass immigrations has been one of the most relevant debates in the recent historiography of Argentina. This paper analyzes the problem in one of the secondary cities of the Argentinian Pampa, Mar del Plata, focusing on the Spanish group. After a macrostructural approach that shows the differential distribution of the ethnic groups in the urban space between 1920 and 1930, the article examines a chain migration movement from Pola de Gordon (Leon, Spain) to Mar del Plata. Using a framework of social anthropology, the article proposes a non-linear relation between settlement and ethnic persistence. The microanalytic approach enlightens the spatial mobility and, beyond this fact, the continuity of the original family and kinship links.