evidence: Since May 2020, tensions have been simmering between India and Nepal over the historically disputed territory of Kalapani. These tensions threaten to boil over with the Parliament of Nepal passing a Constitutional Amendment Bill that alters the country’s maps to include this strategically key area within its borders. This has been widely perceived as an act of cartographic aggression by Indian officials. As with any border dispute, it would be useful to unscramble this diplomatic standoff through a legal prism. Of particular import are some of the questions that this issue raises in connection with river boundaries and cartographic assertions. [...] The Kalapani dispute is symptomatic of an egregious marriage between natural geographies and modern-day Westphalian states. The status of River Kali as a boundary river between India and Nepal lies at the heart of this dispute. The predisposition of these nation-states towards permanent sovereignty and clearly demarcated borders has been vexed by the indeterminacy and transitory nature of Kali. [...] What appeared to be a straightforward provision in this treaty, however, was rendered incongruous by the topography of Kali. It was asserted by Nepal that the source of Kali was located in the mountains near Limpiyadhura, which is higher in altitude than the rest of the river’s flow. In keeping with this reasoning, it laid claim to the land that stretched downwards from Limpiyadhura and extended to the East. Conversely, India contended that the source of the river was situated further east in Kalapani, a sliver of land wedged between the borders of India, Nepal, and the Tibetan Autonomous Region of China.