Preonzo is a former municipality in the district of Bellinzona in the canton of Ticino in Switzerland.

They granted the villages its statutes and customary rights (Statuti, ordini), although, in contrast to Moleno, it was not incorporated in the Levantine.

Together with Gnosca and Moleno it was one of the three churches that used the Ambrosian Rite in the County of Bellinzona.

[2] Traditionally, the village economy was based mostly on alpine pasturage and agriculture.

[2] Preonzo has an area, as of 1997[update], of 16.44 square kilometers (6.35 sq mi).

The rock wall ("Valegión", "Purscì")[4] at Alpe di Roscioro (or Roscèro) at 1,517 m (4,977 ft) above sea level[4] about 2,000 m (6,600 ft) from the Preonzo industrial park has collapsed several times in the past centuries.

In 1702,[5] 1725,[6] and 1747,[7] rock slides and debris destroyed parts of the old town, and boulders have been found over 400 m (1,300 ft) from the base of the slope.

In the 1970s, a small retaining wall for 3,000 m3 (3,900 cu yd) of rock was built in preparation for construction of the motorway in the following decade.

On 7–8 May 2002, about 150,000 m3 (200,000 cu yd) of rock fell over 7 hours during heavy rain from Roscioro.

[clarification needed] Only a few boulders reached the partly completed retaining wall.

[11] During the night of 14–15 May 2012, there was a major rockslide above Preonzo which resulted in no deaths or damaged buildings, but did cause road closures (at intervals even the motorway).

[12][13] The blazon of the municipal coat of arms is Per pale Gules in base a Mill Wheel Or and of the last in chief a Bar embowed of the first and overall a Bend wavy Argent.

[16] The age distribution, as of 2009[update], in Preonzo is; 51 children or 9.1% of the population are between zero and nine years-old and 65 teenagers or 11.5% are between 10 and 19.

[17] The historical population is given in the following table:[2][22] The entire village of Preonzo is designated as part of the Inventory of Swiss Heritage Sites[23] In the 2007 federal election, the most popular party was the FDP which received 47.61% of the vote.

[24] In the 2007[update] Gran Consiglio election, there were a total of 420 registered voters in Preonzo, of which 298 or 71.0% voted.

[17] There were 215 residents of the municipality who were employed in some capacity, of which females made up 37.7% of the workforce.

[17] From the 2000 census[update], 396 or 81.8% were Roman Catholic, while 25 or 5.2% belonged to the Swiss Reformed Church.

In the lower secondary school system, students either attend a two-year middle school followed by a two-year pre-apprenticeship or they attend a four-year program to prepare for higher education.

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