Onno lies at the foot of a high cliff, the Sasso di Onno, and its old core stood further south, near the little church of Sant'Anna, until a flood destroyed it in 1896; the church still stands. In the village is Casa Corti, the former parish house, with the remains of a fresco dated 2 December 1452 and attributed to Cristoforo da Seregno and his workshop, like those in the apse of the nearby parish church of San Pietro and on the north wall of Sant'Anna. Vassena, in the middle, where the town hall is, was founded by settlers from Mandello, on the far shore, who came to farm the land by rowing the few kilometres of lake in the boats called “Lucie”.
Limonta, the northernmost hamlet, is the oldest: in 835 the Emperor Lothair gave it to the monastery of Sant'Ambrogio in Milan, which held it for more than nine centuries, until the French arrived. It remained a legal island inside the State of Milan until 10 September 1797. The church of Santi Ambrogio e Bernardo has a Baroque interior and a late fifteenth-century polyptych of the Crucifixion, and just beyond the village, on the shore, stands the sanctuary of the Madonna del Moletto, a small seventeenth-century church on two levels.