This chapter presents a new, annotated translation of the prose Anaplous Bosporou (Upstream Voyage on the Bosporos) by one Dionysios of Byzantion, written around the middle of the 2nd century AD. As the chapter introduction shows, this striking prose work is ‘perhaps the most detailed description of a landscape to have survived from the ancient world’, and expresses Dionysios’ admiration for his homeland. It also preserves a host of invaluable topographical details along both shores of the Thracian Bosporos and in the Golden Horn (especially the locations of sacred places), as well as information about fisheries. A new, detailed map shows many of the localities mentioned, with an inset showing the area immediately around Byzantion in more detail.