In the 1890s, some Boers trekked into Mashonaland, where they were concentrated at the town of Enkeldoorn, now Chivhu. After the second Boer War, more Boers left South Africa. Starting in 1902 a large group emigrated to the Patagonia region of Argentina (most notably to the towns of Comodoro Rivadavia and Sarmiento). Another group emigrated to British-ruled Kenya, from where most returned to South Africa during the 1930s as a result of warfare there amongst indigenous people. A third group, under the leadership of General Ben Viljoen, emigrated to Chihuahua in northern Mexico and to states of Arizona, California, New Mexico and Texas in the south-western USA. Others migrated to other parts of Africa, including German East Africa (present day Tanzania, mostly near Arusha).