Since the 15th century, the territory now known as Senegal has piqued the interest of European colonising powers.
By the end of the 17th century, France had established authority over the territory surrounding current Dakar, effectively serving as a staging point for the Atlantic slave traffic. It wasn't until the middle of the nineteenth century that the French expanded their influence farther onto the mainland, conquering nearly all of the local kingdoms.
Senegal and French Sudan joined in April 1959 to establish the Mali Federation. On April 4, 1960, a transfer of power deal with France was concluded, paving the way for actual independence on June 20, 1960.
The Mali Federation proved to be short-lived, dissolving on August 20, 1960, when Senegal declared independence. A month later, French Sudan (formerly known as the Republic of Mali) followed likewise.
Mali does not mark its independence from France as a National Day. Instead, they commemorate September 22nd, the day that the Republic of Mali gained independence from the Mali Federation.
