Hydrological networks play a significant role in navigation, migration, ontology. and subsistence among Siberian Indigenous peoples. Yet little research has been done on how Indigenous people transmit the knowledge of hydrological systems across generations and which strategies they use to choose and name key water arteries. This chapter discusses naming principles and toponymical affixes in their relation to the phenomenology and ethnogeography of riverine names in two Indigenous Evenki communities. The river as a landscape feature is a core concept in Evenki culture. Rivers have long served as the reliable water routes helping Evenki to travel, orient, organize, and make sense of space. Our data is based on hydrological sketch maps and interviews with Evenki participants, as well as on a valuable collection of archival maps gathered by prominent Soviet researcher Glafira Vasilevich. We demonstrate that Evenki place-naming strategies differ in terms of the choice of the rivers to be named, the motivation for naming and the transmission of the names to the next generation. Evenki employ flexible naming strategies and may replace, modify, and even abandon their riverine names.