The only island on Lario is Isola Comacina, situated in the commune of Tremezzina, at the inlet of the western coast of the Como branch, between Argegno and the Lavedo peninsula.
The island saw rise on its land numerous churches, including one of the most important basilicas, S. Eufemia. Besides religiously, Comacina held an important political and economic position thanks to its strategic system of fortifications.