It can be read from the Livonian Chronicle of Henry that the history of the county goes back to the 13th century when the Germans conquered the settlement. By the Chronicle the Ümera River was the borderline between Estonia and Latvia. Historians suggest that the Säde River was the borderline, flowing through the northern part of Tireli Bog and falling into Lake Burtnieks. Meadows and forests surrounding the big Tireli Bog and the upper stream of the River Säde were probably even wider and impassable at that time and therefore functioning perfectly as a border.