Adaja
The Adaja near Ávila
Location
Country	Spain
Physical characteristics
Source
• location	Fuente Berroqueña
• coordinates	40°32′22.57″N 5°09′10.09″W / 40.5396028°N 5.1528028°W / 40.5396028; -5.1528028
Mouth
• location	Douro
• coordinates	41°31′59.53″N 4°51′47.81″W / 41.5332028°N 4.8632806°W / 41.5332028; -4.8632806
Length	163 km (101 mi)
Basin size	5,328 km2 (2,057 sq mi)
Basin features
Progression	‹See Tfd› Douro→ Atlantic Ocean
Tributaries
• right	Eresma

The Adaja^[a] is a river located in the centre of the Iberian Peninsula, in Spain. A major left-bank tributary of the Douro,^[1] it flows 163 kilometres (101 mi), and its river basin drains an area of 5,328 square kilometres (2,057 mi²).^[2]

It has its source in the so-called Fuente Berroqueña (Villatoro, province of Ávila), near the saddle point between La Serrota [es] and the Sierra de Ávila.^[2] Initially following a southwest-northeast course through the Amblés Valley, the Adaja then bends northward in Ávila, later receiving the contribution of its most important tributary, the Eresma, near Matapozuelos.^[3] It empties into the Douro in the province of Valladolid near the town of Aniago [es].^[4]