Based on figures from the Central Statistical Agency in 2005, Seleh Leha has an estimated total population of 7,391, of whom 3,529 were males and 3,862 were females. The 1994 census reported it had a total population of 4252 of whom 1,879 were males and 2,373 were females. It is the larger of two towns in Medebay Zana woreda.
Two British hunters passed through Seleh Leha and its neighbor Beles in January 1923, later describing them in unflattering and dismissive words. In February 1936, during the opening moves of the Second Italian-Abyssinian War, the Blackshirt "21st April" Division, with the "Gavininana" and "Gran Grosso" Divisions clashed with the soldiers of Ras Imru Haile Selassie near Seleh Leha, as part of the Second Battle of Tembien.
During the Italian occupation, a leprosarium was built in Seleh Leha; this was abandoned by its Italian staff on 30 March 1941, and later pillaged and destroyed by the locals. The town was later the center of a number of battles between the 604th Army Corps of the Derg and troops of the Tigrayan People's Liberation Front (TPLF) until its capture by the TPLF and the Eritrean People's Liberation Front at the end of February, 1989.