L’articolo segnala – anche sulla base dell’esperienza personale di ricerca - alcune sedi conservative in Italia, Argentina e Uruguay, dove si custodiscono fondi documentari utili allo studio dell’emigrazione italiana nel “Mediterraneo Rioplatense”: una vasta area, compresa tra Argentina e Banda Orientale, attraversata dai fiumi navigabili Uruguay, La Plata e Paraná e dai loro affluenti. Vengono presi in considerazione, oltre ai più noti Archivi pubblici, anche alcune sedi conservative ecclesiastiche e private, queste ultime appartenenti a Fondazioni, Musei e Associazioni di emigrati all’estero.The article points out - even on the basis of personal experience - some conservation sites in Italy, Argentina and Uruguay, where documentary collections are preserved. Such collections are useful for the study of Italian immigration in the "Rioplatense Mediterranean", i.e. in the vast area between Argentina and Banda Oriental, crossed by Uruguay, La Plata and Paraná rivers and their tributaries, still perfectly navigable nowadays. Besides the best known Public Archives, the ecclesiastical and the private ones are taken into account, the latter belonging to foundations, museums and immigrants' associations.