[4] In the High Middle Ages, members of the Langobard military family, the de Sessa formed a noble corporation with lands centered in the current municipality.

The noble corporation remained in power around the village until the reign of the Swiss Confederation.

Due to the tradition of imperial immediacy in the Malcantone region (including Sessa, Astano, and Monteggio), the Bishop of Como lacked the landlord rights he held in neighboring villages.

By the 16th century, and perhaps even before then, they founded an independent parish which also included Monteggio, Castelrotto, and Cremenaga.

The parish church of San Martino was first mentioned in 1288, and its present form dates back to 1630.

In addition to San Martino, the city has several other chapels and churches, including S. Orsola (established 1601).

At the time of the Swiss Confederation rule, the capitano reggente of Lugano was the bailiff in Sessa.

In the 19th century local companies exploited the peat layer at Prati Vergani and gold mines at Monte Sceree (between Sessa and Astano).

They were vassals of the House of Hohenstaufen when they lived in Sessa Castle, which controlled the passage over the Tresa river.

Around the 13th century, a (de) Sessa was mentioned who bore the Capitanei title in Locarno.

As members of the Capitanei of Locarno in the 14th century, they possessed patronage rights to the chapel of S. Orsola in the church of S. Martino in Sessa.

[5] Anyway, other minor lines have survived and the family, still flourishing, is present on the Libro d'Oro della Nobiltà Italiana and on the Annuario della Nobiltà Italiana with the title of Noble.

It consists of the village core of Sessa and the surrounding settlements of Beredino, Bonzaglio, Costa, Lanera and Suino.

The blazon of the municipal coat of arms is Gules a castle with two towers argent ensigned with a swan of the same.

[8] The age distribution, as of 2009[update], in Sessa is; 60 children or 8.9% of the population are between 0 and 9 years old and 72 teenagers or 10.7% are between 10 and 19.

[9] The historical population is given in the following chart:[4][14] The entire village of Sessa is designated as part of the Inventory of Swiss Heritage Sites.

[16] In the 2007[update] Gran Consiglio election, there were a total of 475 registered voters in Sessa, of which 300 or 63.2% voted.

[19] From the 2000 census[update], 447 or 74.0% were Roman Catholic, while 62 or 10.3% 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.