As the crow flies, the distance between Benin and Burkina Faso’s tripoints with Niger and Togo is only around 190 km, but the boundary between the two countries meanders along the Mekrou River in the east, the watershed of the Chaîne de l’Atacora massif, and the Pendjari River in the west, producing a total boundary length of 440 km. The territories of modern-day Benin and Burkina Faso were the subject of much administrative tinkering by France through the late 19th and early 20th centuries, and a general description of the boundaries of Dahomey (modern-day Benin) issued by France in 1938 remains the only formal definition of the Benin–Burkina Faso border today. The two countries dispute sovereignty over a small area known as Kourou/Koalou near the tripoint with Togo, which has been declared a neutral zone pending settlement of the dispute. In 2009, an agreement to refer the dispute to the International Court of Justice was signed, but no formal application has yet been made to the Court.