Cesky Tesin is a town in the Karvina District, Moravian-Silesian Region of the Czech Republic. The town is commonly known in the region as just Tesin. It lies on the West Bank of the Olza River, in the heart of the historical region of Cieszyn Silesia. Until the 1920 division of the region between Poland and Czechoslovakia it was just a western suburb of the town of Teschen, which after the division fell to Poland as Cieszyn.
Until 1918 the area was called Sachsenberg meaning Saxon Hill and was a small western suburb of the town of Teschen in the Duchy of Teschen, within Cieszyn Silesia of Austria-Hungary.