In 1900, present-day Senegal was part of French Sudan. French Sudan and Senegal formed the Federation of Mali in 1959. In 1960, the Federation of Mali became independent and split up into its two original components, Sudan and Senegal.
Presently, Senegal consists of 14 regions; three of these were created in 2008: Kaffrine, Kédougou, and Sédhiou. They were formed by taking the homonymous departments from Kaolack, Tambacounda, and Kolda regions, respectively.
The regions are further subdivided into departments.
References:
http://www.statoids.com/usn.html
