Map of the maximum extend of Boko Haram's territorial control in West Africa's Lake Chad region, in mid-January 2015. After the Lake Chad African nations joined together in a Coalition to defeat Boko Haram, Boko Haram lost most of its territory by March 2015. On March 7, 2015, Boko Haram pledged allegiance to ISIL, becoming ISIL's West African province of Wilāyat al Sūdān al Gharbī.