Ventrosa or Ventrosa de la Sierra is a mountainous municipality in the autonomous region of La Rioja in the basin formed by the River Najerilla.
-Location: It is part of the district of Nájera. It is in the far southeast of the Demanda Mountains upstream of the River Najerilla. It is squeezed into a narrow valley that climbs in height up to Pancorbo.
-Area: 9.4 km2.
-Height: 1,003 metres.
-Economy: Since the '60s, many people have moved away from the town because of the municipality's weak economy based on wool production. In the last few years, rural tourism has increased greatly.