| Caso | |
| Settlement Type: | Municipality |
| Native Name: | Casu |
| Flag Size: | 150 |
| Pushpin Map: | Spain |
| Pushpin Map Caption: | Location in Spain |
| Subdivision Type: | Country |
| Subdivision Name: | Spain |
| Subdivision Type1: | Autonomous community |
| Subdivision Name1: | Asturias |
| Subdivision Type2: | Province |
| Subdivision Name2: | Asturias |
| Subdivision Type3: | Comarca |
| Subdivision Name3: | Nalón |
| Subdivision Type4: | Judicial district |
| Subdivision Name4: | Laviana |
| Seat Type: | Capital |
| Seat: | Campo de Caso |
| Coordinates: | 43.1833°N -26°W |
| Elevation Max M: | 2022 |
| Area Total Km2: | 307.94 |
| Population Demonym: | casín |
| Population Density Km2: | auto |
| Blank Name Sec1: | Official language(s) |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CEST |
| Utc Offset Dst: | +2 |
| Postal Code Type: | Postal code |
| Postal Code: | 33990 - 33999 |
| Area Code Type: | Dialing code |
| Leader Title: | Alcalde |
| Leader Name: | Miguel Ángel Fernández |
| Leader Party: | FSA-PSOE |
Caso (Asturian: Casu) is a municipality in the Spanish Principality of Asturias. It shares a boundary to the North with Piloña; to the East with Ponga; to the South with León and to the West with Sobrescobio and Laviana.
Most of the inhabitants of Caso live in the Nalón Valley, on which the largest town is the capital El Campu. The town is divided in two neighbourhoods: L'Arrobiu and El Barru.
The municipalities of Caso and Sobrescobio together constitute the Redes Natural Park, designated by the UNESCO as a Biosphere Reserve. The Natural Monument of the Cueva Deboyu (the Nalón River passes through a cave in the mountain) is also located in Caso. Caso is famous for its landscape, European beech forests, wood handcraft and its Casín cheese.
In the past, most of Caso's people worked in coal mining and livestock farming. Nowadays, tourism has become one of the more important activities in Caso, but farming is still the most relevant.
The Dam of Tanes provides electric energy and drinking water to the central part of Asturias.
The AS-17 (Avilés - Pass of Tarna) road is the easiest form to reach Caso from Oviedo or Gijón. The AS-254 (El Campu - L'Infiestu) road connects Caso with Piloña and the N-634 road. Caso and León are connected by the Pass of Tarna. The nearest train station is located in Pola de Laviana.
The municipality is located in a wild and mountainous area in which there are plenty of hiking routes and natural places to visit:
There is also some old churches and interesting civil constructions.