Situated in the north-eastern part of the Romanian Plain, Lower Siret Plain is known in literature as one of the youngest and lowest regions of Romania. It is also currently an important area of subsidence, responsible for the convergence of the main rivers flowing from the Carpathian’s and Sub-Carpathian’s Curvature to Siret, the main drainage axis. Following these issues and also due to some human intervention, river beds have suffered over the years many amendments, reflected in the detail geomorphology of the region (dead river beds, abandoned banks, oxbows etc.) and, the most recent, in the cartographic materials. All natural transformations of the river network structure were mainly related to the alluvial contribution of the tributaries with Carpathian and Sub-Carpathian origin, which continuously raised the right part of Siret’s alluvial plain, forcing the river to move eastward and finally determining the recalibration of the entire network. Traces of such an important and recent river bed dynamics are still visible today and are indirectly confirmed by historical documents. These indicate that in some areas, the lower parts of the main rivers are very young. Article examines how the available cartographic materials report recent dynamics of the main rivers of Lower Siret Plain and can explain the age of the present river pattern. Among the conclusions is that the maps made by the end of the seventeenth century and early-twentieth century reflects little of that time geographical realities, that, so far, the Siret river had abandoned its old bed located west of the current and named on various maps - Siretel (Little Siret). In this abandoned river bed continued to flow all the rivers of the SubCarpathian bend, except Buzău river, until the middle of the eighteenth century, when some areas were clogged and tributary rivers have had to extend their lower courses to the new Siret. Thus, the current configuration of the hydrographic network seems to date, with few exceptions,from the first half of the nineteenth century.