Waalo (Waalo) was a kingdom on the lower Senegal River in West Africa, in what is now Senegal and Mauritania. It included parts of the valley proper and areas north and south, extending to the Atlantic Ocean. To the north were Moorish emirates; to the south was the kingdom of Cayor; to the east was Jolof.
Waalo was founded in 1287. The semi-legendary figure Ndiadiane Ndiaye, founder of the Jolof Empire was from this kingdom. Under Ndiadiane Ndiaye in the 14th century, Jolof made Waalo a vassal.
In 1638, the French established the first permanent European trading settlement at the mouth of the Senegal River, moving to the site of Saint-Louis in 1659 while facing consistent military and political pressure from the Brak. The French presence would have a decisive effect on the rest of the history of Waalo.
Economically benefiting from trade with the French, Waalo became de facto independent of the Jolof Empire in the mid 1600s, though the Brak continued to pay symbolic tribute to the Bourba Jolof until 1715.
Partly in response to the shift in trade away from Berber tribes to the French, Nasr ad-Din, a Berber Marabout, launched the Char Bouba War or the Marabout War, overthrowing the ruling aristocracy of Walo (among other Senegal river kingdoms) in an attempt to establish an Islamic theocracy. Upon his death in 1674, however, his movement collapsed and the old hierarchies, aligned with Arab Hassan tribes north of the river and vigorously supported by the French, re-asserted themselves.
Waalo's relatively powerful position in the aftermath of the Marabout Wars dissolved towards the end of the 17th century in a period of civil war between rival aristocratic clans, a pattern that would repeat itself up until the kingdom's downfall. In March 1724, the lord of Bethio Maalixuri, longtime intermediary between Brak Yerim Mbyanik, Saint-Louis, the neighboring kingdom of Cayor and the Emirate of Trarza, attempted to secede from the kingdom, but was defeated and exiled.