|Population||35 (as of December 2004)|
|Area||11.1 km2 (4.3 sq mi)|
|Elevation||996 m (3,268 ft)|
|Maggia, Onsernone, Vergeletto|
Gresso is a municipality of the district Locarno in the canton of Ticino in Switzerland. The municipality was made in 1882 by splitting from the municipality of Vergeletto. On the 10 April 2016 the former municipalities of Gresso, Isorno, Mosogno and Vergeletto merged into the municipality of Onsernone.