This study explores representations of the river Arno in Dante's Divine Comedy. In particular, it builds upon recent cartographic readings of the poem by contextualising Dante's mapping of the Arno within his broader project of re-mapping the entire Italian peninsula across Hell, Purgatory and Paradise in accordance with his subjective – and more often than not polemical – perspectives on the political and ethical state of contemporary Italy.  The first chapter begins by proposing new evidence to suggest that Dante consciously establishes a parallel between the river Phlegethon of Inf. 14 and the river Arno of Purg. 14., a fluvial conflux which opens the poet's moral critique of Italy to new avenues of interpretation. The second half of the chapter will trace the trajectory that the Arno – now superimposed onto the Phlegethon – will traverse across lower Hell, offering a close analysis of the passages in which the river is charted as it passes through the ditches of the Malebolge reserved for the hypocrites and the falsifiers in Inf. 23 and Inf. 20 respectively before making its descent into the final circle of Hell, where in Inf. 33 Dante cartographically aligns the mouth of the Arno with the terminus of the Phlegethon. The chapters which follow discuss the rarer occasions in which the Tuscan river features in the second and third canticles. Specifically, the second chapter examines how the Arno's negative characterisation as an infernal river will change as it performs a central role in the salvation of Bonconte da Montefeltro in Purg. 5, while the final chapter explores how Dante's political ideology and moral ideals are reflected in the mapping of the Arno and Tiber during the episode on the life of Saint Francis in Par. 11.