Castel San Pietro is a municipality in the district of Mendrisio in the canton of Ticino in Switzerland.

[3] A settlement near the village was mentioned in 865, when an Imperial knight named Sigeradus, granted the area to the monastery of Sant'Ambrogio in Milan.

During the war between Milan and Como (1118–27) a castle was built, which was the origin of the municipality's name.

By the mid-13th century, it passed back and forth between the Bishop of Como and the Russ and Rusconi family.

It was later named in memory of the bloody feud between the Bosia and Rusconi family in 1390, as the "Red Church".

The parish church of S. Eusebio was mentioned in 1270, but the existing building dates from the 17th–18th centuries and was restored in 1912.

[3] In the Middle Ages and the early modern era the Catholic Church (Church of S. Fedele and the Bishop of Como) and powerful, local families (Albrici, Rusconi, and after the 15th century, the Turconi, as witnessed by their Villa Turconi a Loverciano) possessed lands in and around the village.

At the beginning of the 20th century, a small industrial base (tobacco processing, distilleries) developed in the valley.

[3] The municipality of Castel San Pietro is located in the district of Mendrisio.

The municipality consists of the village of Castel San Pietro, which is made up of the sections of Corteglia, Gorla, Loverciano, Obino as well as others.

[4] Castel San Pietro has an area, as of 1997[update], of 11.83 square kilometers (4.57 sq mi).

[5] The blazon of the municipal coat of arms is Gules a castle with one tower argent and coupeaux vert.

[8] The age distribution, as of 2009[update], in Castel San Pietro is; 175 children or 8.4% of the population are between 0 and 9 years old and 200 teenagers or 9.6% are between 10 and 19.

The villages of Casima, Castel San Pietro, Campora and Monte are all part of the Inventory of Swiss Heritage Sites.

[15] In the 2007[update] Gran Consiglio election, there were a total of 1,594 registered voters in Castel San Pietro, of which 1,159 or 72.7% voted.

The number of jobs in the primary sector was 42, of which 41 were in agriculture and 1 was in forestry or lumber production.

In the tertiary sector; 58 or 19.7% were in wholesale or retail sales or the repair of motor vehicles, 8 or 2.7% were in the movement and storage of goods, 52 or 17.7% were in a hotel or restaurant, 2 or 0.7% were in the information industry, 5 or 1.7% were the insurance or financial industry, 19 or 6.5% were technical professionals or scientists, 16 or 5.4% were in education and 85 or 28.9% were in health care.

[19] From the 2000 census[update], 1,484 or 85.9% were Roman Catholic, while 87 or 5.0% 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.