The Acueducto de los Milagros ("Miraculous Aqueduct") is a ruined Roman aqueduct in Mérida, Spain, formerly the Roman colony of Emerita Augusta.
Only a relatively small stretch of the aqueduct still stands, consisting of 38 arched pillars standing 25 metres (82 ft) high along a course of some 830 metres (2,720 ft). It is constructed from opus mixtum - granite ashlar blocks interspersed with red brick - utilising a double arcade arrangement. The structure originally brought water to the city from an artificial lake, called the Lago de Proserpina, supplied by the river Aberregas around 5 km (3 miles) to the north-west of Mérida.
It is thought to have been constructed during the 1st century AD, with a second phase of building (or renovations) around 300 AD. In later centuries, the inhabitants of Mérida dubbed it the "Miraculous Aqueduct" for the awe that it evoked.
The aqueduct was one of three built at Mérida, the other two being the 15 kilometres (9.3 mi) long Aqua Augusta, fed by the Cornalvo reservoir, and San Lázaro, fed by underground channels. The aqueduct is preserved as part of the Archaeological Ensemble of Mérida, a UNESCO World Heritage Site.
In the immediate vicinity a small Roman bridge called Puente de Albarregas runs parallel to the arcades.