During the Ancien Régime, Comologno belonged to the Squadra of Crana, which together with the other villages of the valley (with the exception of Auressio) formed the medieval municipality of Onsernone.

With the emergence and development of rye straw processing in the 19th century, the population of Comologno increased rapidly.

Several families became wealthy in foreign countries, and used that wealth to build stately mansions in Comologno.

Another notable mansion is the Palazzo (or Castello) della Barca which was acquired in the 1930s by Vladimir Rosenbaum for his wife Aline Valangin, a writer and artist.

It soon became a haven for artists and well-known anti-fascists, including Ignazio Silone, Ernesto Rossi, Kurt Tucholsky, Hans Marchwitza, Ernesto Bonaiuti, Max Terpis, Elias Canetti, Wladimir Vogel and Jean-Paul Samson.

Since the early 1970s, at the suggestion of the Associazione Amici di Comologno, various artists have decorated houses in the village with frescos.

The present population is made up of retirees and commuters who work in the Onsernone valley and in the agglomeration of Locarno.

Until about the mid-20th century, agriculture, animal husbandry and straw plaiting were the main sources of income in the village.

In 1989, the opening of the Centro sociale onsernonese nursing home provided a few dozen jobs in the village.

The discovery of a Roman tomb from the 1st-2nd Century AD, with pottery and coins, proves that Gresso was part of the outer-most reaches of the Vicus of Muralto.

Until 1803, Gresso was part of the Squadra of Russo, one of five Squadre, that formed the medieval community of Onsernone.

After World War II farming and grazing were almost abandoned and replaced by short-term, seasonal emigration.

[10] One notable building in Auressio is the Villa Edera, which was built in 1887, for the Paris impresario Paolo Antonio Calzonio.

[11] After World War II, much of the village population emigrated and sold their properties to outsiders.

Many people who bought houses in Berzona were well known personalities from the arts and culture, such as Alfred Andersch, Golo Mann and Max Frisch.

Today, the village is shrinking as few jobs in farming and grazing remain and most of the working population have moved to Locarno.

From the Middle Ages until the end of the Ancien Régime Loco was the capital of the old Onsernone valley community.

The church is also the home of a Last Supper painting by the Flemish painter Godefridus Maes from 1683.

In addition to the typical houses with balconies, a number of aristocratic mansions are located in the village.

[12] The primary school for the area is located in Loco, along with the Onsernonese Museum (opened 1966) and the renovated retirement home of the Onsernone valley.

Casa Shira (built in the 19th century, now owned by the community) has a small public library and a hostel.

Before 2016, Onsernone consisted only of the villages of Comologno, Crana and Russo as well as the settlements of Vocaglia, Corbella, Cappellino and Spruga.

[18] The historical population is given in the following tables:[23] The Palazzo Della Barca and the Museo Onsernonese are listed as Swiss heritage site of national significance.

The villages of Comologno, Russo, Gresso, Mosogno di sotto, Auressio, Berzona and Loco are part of the Inventory of Swiss Heritage Sites.

[26] In the 2007[update] Gran Consiglio election, there were a total of 312 registered voters in Onsernone, of which 131 or 42.0% voted.

The professional program lasts three years and prepares a student for a job in engineering, nursing, computer science, business, tourism and similar fields.

[28] In 2014 the crime rate, of the over 200 crimes listed in the Swiss Criminal Code (running from murder, robbery and assault to accepting bribes and election fraud), in Onsernone was 51 per thousand residents, slightly lower than the national average (64.6 per thousand).

During the same period, the rate of drug crimes and violations of immigration, visa and work permit was 0 per thousand residents.

The wettest month is September during which time Mosogno receives an average of 244 mm (9.6 in) of rain or snow.

At bottom, the coat of arms shows two waves of water symbolizing the River Isorno which carved the Onsernone Valley.