Mosogno is a former municipality in the district of Locarno in the canton of Ticino in Switzerland . On 10 April 2016 the former municipalities of Vergeletto , Gresso , Mosogno and Isorno merged into the municipality of Onsernone .

Mosogno is first mentioned in 1277 as Mosogno. In 1352, it was mentioned as Muxognio. In the Middle Ages, it was one of the five squadrons that made up the community of Onsernone. It became an independent municipality in 1803.