Sierra de Toloño (Basque: Toloñoko mendilerroa) is a mountain range of the Sierra de Cantabria, located in the province of Álava in the Basque Country, northern Spain. From the west, the range rises from the Conchas de Haro where the River Ebro enters the region of La Rioja at 445 metres above sea level, and from there runs east forming the northern border of the Rioja Alavesa, separating the Rioja region from the rest of Álava. Its highest point is Mount Toloño at 1271 metres above sea level in the municipality of Labastida.