The Upper Thracian Plain (, Gornotrakiyska nizina) constitutes the northern part of the historical region of Thrace. It is located in southern Bulgaria, between the Sredna Gora mountains to the north and west; the Rhodopes, Sakar and Strandzha to the south; and the Black Sea to the east. A fertile agricultural region, the Upper Thracian Plain proper has an area of and an average elevation of . The plain is part of Northern Thrace (Северна Тракия, Severna Trakiya). The climate is transitional continental. The highest temperature recorded in Bulgaria occurred here: it was at Sadovo in 1916. The precipitation is a year. Important rivers are the Maritsa and its tributaries, the Tundzha, the Stryama, the Topolnitsa, and the Vacha.