Lake Valgjärv is one of the most beautiful lakes in Valga county and maybe in the whole southern Estonia as well. The lake gets suddenly deep only a couple of metres from the banks, reaching 10-15 metres at the average (the deepest point 26,8m). Unlike other lakes of Koorküla, the coastline of Lake Valgjärv is full of coves. Its banks are high and steep and covered with thick forest from three sides. The eastern bank of the lake is a narrow mound with Emasoo swamp behind it.
According to folk-tales Lake Valgjärv got its name for its exceptionally transparent water. They say that once upon a time a fine manor was standing on the exact spot where the lake is today. It sank under water during the wedding of a landlord who married his sister.
In 1958 the bottom of Lake Valgjärv was explored and a long ridge was discovered in the middle of it. The water level above it was only 1-2 m. The ruins of the building - 74 conifer logs (each log about 9 m long with the diameter of 30 cm) were discovered on that spot. The pottery found between them in the mud allows to assume that these were the remains of a fortified settlement dating from the second half of the first millennium.