47,549 km2 (18,359 sq mi) were defined according to the Treaty of Tartu in 1920 between Estonia and Russia. Today the remaining 2,323 km2 (897 sq mi) are nowadays part of Russia. The ceded areas include the Petserimaa county and the boundary in the north of Lake Peipus as the Lands behind the city of Narva including Ivangorod (Jaanilinn).[5][6]