Châtel-Saint-Denis (ʃɑtɛl sɛ̃ d(ə)ni; Châtél, locally Tsathi tsaˈθi, or Châtél-Sent-Denis, locally Tsathi-Chin-Dèni) is a municipality and district capital of the district of Veveyse in the canton of Fribourg in Switzerland.
Châtel-Saint-Denis has an area of . Of this area, or 46.7% is used for agricultural purposes, while or 42.3% is forested. Of the rest of the land, or 7.0% is settled (buildings or roads), or 0.6% is either rivers or lakes and or 3.4% is unproductive land.
Of the built up area, housing and buildings made up 3.3% and transportation infrastructure made up 2.5%. Out of the forested land, 38.4% of the total land area is heavily forested and 3.8% is covered with orchards or small clusters of trees. Of the agricultural land, 2.1% is used for growing crops and 17.0% is pastures and 27.5% is used for alpine pastures. All the water in the municipality is flowing water.
The capital of the Veveyse district is located on the banks of the Veveyse river, on the Bulle-Vevey road. It consists of the village of Châtel-Saint-Denis, the ski and hiking areas of Les Paccots and Fruence and a number of hamlets. The large municipality includes the Lac de Lussy and Lac des Joncs nature preserves.
The blazon of the municipal coat of arms is Or an Eagle displayed Sable.
Châtel-Saint-Denis has a population () of . , 23.1% of the population are resident foreign nationals. Over the last 10 years (2000–2010) the population has changed at a rate of 36.2%. Migration accounted for 28.6%, while births and deaths accounted for 3.5%.
Most of the population () speaks French (3,909 or 89.1%) as their first language, Portuguese is the second most common (193 or 4.4%) and German is the third (118 or 2.7%). There are 34 people who speak Italian.
the population was 50.5% male and 49.5% female. The population was made up of 2,110 Swiss men (37.3% of the population) and 743 (13.1%) non-Swiss men. There were 2,178 Swiss women (38.5%) and 622 (11.0%) non-Swiss women. Of the population in the municipality, 1,634 or about 37.