Coordinates: 50°27′32″N 4°52′52″W / 50.4589°N 4.8811°W
Rosenannon (Cornish: Ros an Onnen) is a hamlet in Cornwall, England, United Kingdom. It is within the civil parish of St Wenn, 4 miles (6.4 km) south-west of the town of Wadebridge.
Rosenannon Downs is a nature reserve to the north of the hamlet owned and managed by the Cornwall Wildlife Trust.