A province of medieval Livonia corresponding to the southwestern part of modern Estonia. Sakkala was delimited to the north by the river Nawwest (mod. Navesti, Estonia), to the east by Lake Wirzjarw (mod. Vôrtsjarv), and to the west by massive swamps. The main provincial centers according to the chronicle of Henry of Livonia were Fellin (mod. Viljandi) and Leole (mod. Lohavere).
Raids into Sakkala by the German crusaders based in and around Riga began in 1208 and were met by counterattacks from the Estonian inhabitants in the province. One of the chieftains of Sakkala, Lembitu of Leole, was singled out by Henry of Livonia as one of the fiercest enemies of Riga. He emerged as one of the heroes of Estonian national historiography in modern times. In 1215, after the capture of Leole and Fellin, the population of the province was baptized. However, resistance was not broken until 1217, when the crusaders defeated the Estonian forces in the battle of Fellin, in which Lembitu lost his life.
The new German administration, with its center in Fellin, suffered a serious blow from an Estonian uprising in January 1223, but Sakkala was finally subjected by the Order of the Sword Brethren in August that year. The province became one of the core areas of the Livonian branch of the Teutonic Order after it incorporated the remnants of the Sword Brethren in 1237.