Grandfontaine (French pronunciation: [ɡʁɑ̃fɔ̃tɛn]) is a municipality in the district of Porrentruy in the canton of Jura in Switzerland.

The large fountain and the bath house, both from the 19th century, are located on the karst spring that gave this village its name.

The blazon of the municipal coat of arms is Or a Cross Sable between 20 billets of the last.

[9] Most of the population (as of 2000[update]) speaks French (301 or 91.2%) as their first language, German is the second most common (28 or 8.5%) and English is the third (1 or 0.3%).

[9] The historical population is given in the following chart:[3][13] In the 2007 federal election the most popular party was the CVP which received 40.57% of the vote.

In the federal election, a total of 106 votes were cast, and the voter turnout was 39.4%.

[9] There were 154 residents of the municipality who were employed in some capacity, of which females made up 39.6% of the workforce.

In 2008[update] the total number of full-time equivalent jobs was 94.

In the tertiary sector; 21 or 70.0% were in wholesale or retail sales or the repair of motor vehicles, 3 or 10.0% were in a hotel or restaurant, 2 or 6.7% were in education.

[9] From the 2000 census[update], 281 or 85.2% were Roman Catholic, while 19 or 5.8% belonged to the Swiss Reformed Church.

This is followed by three years of obligatory lower Secondary school where the students are separated according to ability and aptitude.