Penthaz is a municipality in the district of Gros-de-Vaud in the canton of Vaud in Switzerland. History Penthaz is first mentioned in 1011 as Penta. Geography Penthaz has an area, , of . Of this area, or 67.1% is used for agricultural purposes, while or 13.6% is forested. Of the rest of the land, or 17.5% is settled (buildings or roads), or 0.8% is either rivers or lakes and or 1.8% is unproductive land. Of the built up area, industrial buildings made up 1.6% of the total area while housing and buildings made up 8.9% and transportation infrastructure made up 5.5%. Power and water infrastructure as well as other special developed areas made up 1.3% of the area Out of the forested land, 12.0% of the total land area is heavily forested and 1.6% is covered with orchards or small clusters of trees. Of the agricultural land, 61.1% is used for growing crops and 5.7% is pastures. Of the water in the municipality, 0.5% is in lakes and 0.3% is in rivers and streams. The municipality was part of the Cossonay District until it was dissolved on 31 August 2006, and Penthaz became part of the new district of Gros-de-Vaud. The municipality is located on the left bank of the Venoge river. Coat of arms The blazon of the municipal coat of arms is Azure, a Bend wavy Argent, overall a Column Or. Demographics Penthaz has a population () of . , 17.8% of the population are resident foreign nationals. Over the last 10 years (1999–2009 ) the population has changed at a rate of 13.8%. It has changed at a rate of 8% due to migration and at a rate of 5.7% due to births and deaths. Most of the population () speaks French (1,150 or 89.4%), with German being second most common (49 or 3.8%) and Italian being third (32 or 2.5%). Of the population in the municipality 243 or about 18.9% were born in Penthaz and lived there in 2000. There were 581 or 45.1% who were born in the same canton, while 209 or 16.2% were born somewhere else in Switzerland, and 247 or 19.2% were born outside of Switzerland. In there were 8 live births to Swiss citizens and 2 births to non-Swiss citizens, and in same time span there were 3 deaths of Swiss citizens and 1 non-Swiss citizen death. Ignoring immigration and emigration,