Historically, the name Mandera has been attributed to Madheer, Cordia sinensis, a fruit plant very common in Mandera.

Records from the Kenya National Archives show the British East Africa Protectorate was present in around 1890s though the British Colony of Kenya established a permanent post in around 1910 covering Mandera from Moyale Post. Tribes present in Mandera region were Garre, Murule, Degodia and some Corner Tribes. Merchant Arabs and other non-local Somalis were there doing business in around Rhamu. British Colonists started recording events as early as 1893 including the ‘Colka Caalin’ of the 1915 between Garre on one side and Degodia and Murule on another side.

Among the notable incident of Mandera history was the The Rhamu Incident of the 1977 in which Somalia Military Invaded Ethiopia defences from the Kenyan side. Some 1500 Somali soldiers attacked a border post and killed 30 Kenyan police officers and soldiers. Because Mandera is inhabited by Somalis, who resemble those of Somalia and Ethiopia, the Somalia army successfully crossed into the Sidamo Region of Ethiopia in the so called Ogaden War.