Arnedillo is located in the Upper Valley of the River Cidacos, declared a Biosphere Reserve by UNESCO in 2003. At an altitude of 651 metres and covering an area of 48 km², it forms part of the Arnedo region and is 62 km from Logroño and 27 km from Calahorra.
Its surroundings, which include Peña Isasa, Peñalmonte and Las Peñas de Arnedillo, are part of the Natura 2000 Network, offering landscapes of great ecological value and mountain trails.
The first references to the town appear in the Middle Ages: Count Fernán González mentioned it in the 10th century as Arnietello. From 1170 onwards, it was a royal town by privilege of King Alfonso VII. Today, Arnedillo is known for its thermal waters and its privileged natural environment.