The frontier between Siam and Cambodia starts, on the left shore of
the Great Lake, from the mouth of the river Stung Roluos, it follows
the parallel from that point in an easterly direction until it meets the
river Prek Kompong Tiam, then, turning northwards, it merges with
the meridian from that meeting-point as far as the Pnom Dang Rek
mountain chain. From there it follows the watershed between the
basins of the Nam Sen and the Mekong, on the one hand, and the Nam
Moun, on the other hand, and joins the Pnom Padang chain the crest of
which it follows eastwards as far as the Mekong. Upstream from that
point, the Mekong remains the frontier of the Kingdom of Siam, in
accordance with Article 1 of the Treaty of 3 October 1893.