Gerra (Gambarogno
) is a former municipality in the district of
Locarno 
in the canton of Ticino in Switzerland.
On 25 April 2010, the former municipalities of
Caviano 
,
Contone 
, Gerra Gambarogno,
Indemini 
,
Magadino 
,
Piazzogna 
, San Nazzaro, Sant'Abbondio and Vira Gambarogno merged in the new municipality of Gambarogno.
History
The name Gerra is probably from the 18th century, when the village of Ronco de Martignoni (which was first mentioned in 1591) expanded into the Gerra river delta and the shores of
Lake Maggiore 
.
Gerra was part of the old Vicinanza of Gambarogno. In the 16th century, Ronco de Martignoni, Ronco di Sopra and Scimiana joined to form an independent municipality. This municipality is listed in the register of lands of the parish of S. Abbondio from 1596.