Sarsi (särˈsē) [key], Native North Americans whose language belongs to the Athabascan branch of the Nadene linguistic stock (see also Native American languages). They are also known as the Sarcee. At the beginning of the 19th cent., their hunting grounds were on the upper Saskatchewan River. Attacks by the Cree and other tribes caused the Sarsi to ally themselves with the Blackfoot for protection. Although their customs were greatly modified by association with this Plains tribe, their language remained unaffected. In 1877 they ceded their lands to the Canadian government and in 1880 moved to a reserve at Calgary, Alberta. There were some 800 Sarsi in Canada in 1991.