Gauja

The Gauja (Estonian and Livonian: "Koiva"; German: "Livländische Aa", see Aa River) is one of the longest rivers in Latvia with a length of 452 km and a catchment area of 8900 km². Its source is in the hills southeast of Cēsis. It first flows east and north and forms the border with Estonia for about 20 km. South of Valga and Valka, it turns west towards Valmiera, continuing southwest near Cēsis and Sigulda. The Gauja flows into the Baltic Sea northeast of Riga.

In Cesis district and Riga district the Gauja has shaped the deepest river valley in Latvia with up to 90 m high banks. This part of the Gauja valley contains numerous natural and cultural landmarks and was declared a national park (Gauja National Park) in 1973.