Santo Adriano (Asturian: Santu Adrianu) is a municipality in the Autonomous Community of the Principality of Asturias.

In addition to the Trubia, which crosses the territory from south to north, there are many small arroyos which flow into it, such as the Picarós, the Rebregáu, the Tresarcu and the Xanas.

The large part of the movement is due to the migration of many inhabitants to Oviedo, especially for working in the arms factory in Trubia parish.

The most common breed of cattle is the Asturiana de los Valles, which is bred for meat.

The most notable building in the municipality is the temple of Santo Adriano de Tuñón, which was ordered built by Alfonso III of Asturias and his wife the queen Jimena in 891.