A regional town, not a museum piece
Porrentruy stands in Ajoie, the north-western part of the Canton of Jura, close to the French border. The Allaine runs through this compact town, where a castle ridge, an old street plan and a working district centre sit within an easy walk of one another. The permanent resident population of the whole municipality was 6,597 on 31 December 2025, according to the Jura cantonal statistics office. That figure describes the commune, not just the historic centre. Porrentruy is small enough to explore on foot, yet it serves villages across Ajoie with schools, public services, courts, shops and transport links.
The town rewards a slower visit. From the station, the older streets lead toward the castle and the civic buildings; cafés, restaurants and everyday businesses still occupy the centre. The impression is not of a preserved set but of a place whose administrative and commercial life grew around a position that was once politically strategic.
From the prince-bishops to the Canton of Jura
Porrentruy became an important residence of the Prince-Bishops of Basel, and the castle above the town remains the clearest expression of that authority. The story is more layered than a single “founding” date: the settlement’s political role changed repeatedly as borders and governments shifted. During the French Revolution, the Bishop of Basel fled in 1792. French rule followed; between 1793 and 1814 Porrentruy belonged to French administrative departments and served for a time as a departmental capital. The Congress of Vienna settled the region’s post-Napoleonic status in 1815, and Porrentruy was attached to the Canton of Bern.
The nineteenth century brought a different kind of transformation. Watchmaking and other industry expanded, and the railway arrived from France in 1872; the line to Delémont opened in 1877. Rail traffic helped trade and brought new prosperity, visible in the Belle Époque houses built beyond the older core. In 1913 the station ranked fourth in Switzerland by the tonnage of freight passing through it, a reminder of how connected this border town once was. After the creation of the Canton of Jura was accepted in 1974, the new canton entered into sovereignty in 1979. Porrentruy lost its capital and prefecture status, but remains the district centre and still hosts cantonal services, educational institutions and the courts.
Another chapter of local history is remembered through Pierre Péquignat and the Ajoie “commis,” who led a revolt against the Prince-Bishop’s centralizing policies from 1727 to 1740. The movement was real; its leaders were executed in front of the town hall on 31 October 1740. Their story now appears in the Circuit Secret, a key-based visit that opens normally closed spaces in the castle and old town, using sound and light as well as historical interpretation. The route also brings the Vouivre, a legendary Jura creature associated with water, into the experience. Folklore is presented as folklore, alongside documented political conflict.
Read the town through its buildings
Begin at the castle courtyard and the Tour Réfous, the old keep above the roofs. The courtyard and tower are generally open to visitors during daytime hours, but access can change, so check before setting out. From the esplanade, look down over the compact historic centre and then descend into the lanes. The Hôtel de Ville, Hôtel des Halles, Hôtel de Gléresse and the former Hôtel-Dieu show how civic, commercial and religious life acquired a Baroque setting in the eighteenth century. A building programme started under the Prince-Bishops in 1744; architects Gaspare Bagnato and Pierre-François Paris are associated with some of the period’s work.
The Hôtel-Dieu is particularly useful for understanding the town beyond its façades. It served as a hospital from 1765 to 1956 and now houses a regional museum. Its pharmacy, furnished in 1846, preserves the memory of the former hospital; collections also cover church art, prints, photography and Jura horology. It is distinct from JURASSICA’s natural-history Museum, which is temporarily closed for renovation from September 2025, with reopening planned for the end of 2027. Check both institutions’ current schedules before visiting.
For a guided walk, the local tourism office offers visits that explain the buildings through social history as well as architecture. The Circuit Secret is a more theatrical alternative for people who want access to normally locked corners. It can include unusual spaces in and around the castle and old town and should be booked or collected through the official visitor service.
Beyond the walls: fossils, gardens and Ajoie
Porrentruy’s other signature story is much older than the town. In the Late Jurassic, around 152 million years ago, dinosaurs left footprints in the region’s limestone. At Dinotec, more than one hundred genuine track impressions are displayed in the courtyard of the technical school, protected under glass. The site is free and open around the clock from April through October. The nearby educational trail at Courtedoux takes about an hour on a mostly level route and ends at sauropod tracks; it is also free and seasonal. JURASSICA’s Banné fossil-dig site offers a more hands-on activity on selected afternoons from April to October. Confirm the day’s opening before travelling, especially late in the season.
The botanical garden and greenhouses offer a quieter pause in town, while the orchards and villages of Ajoie make easy regional extensions. Porrentruy is also a practical base for visitors interested in local food, cycling and small-town heritage rather than a single headline attraction. Hotels, guest accommodation, cafés and restaurants give visitors basic services in the centre; the tourism office can advise on guided visits, seasonal openings and regional walks.
Getting there and planning a visit
The railway station connects Porrentruy with the wider Jura network. Under the timetable introduced in December 2025, trains run twice an hour toward Delémont, where passengers can change for Basel, Laufen or Biel. Once each hour, an IC51 service continues through to Lausanne via Neuchâtel. There are also two trains per hour to Delle and to Bonfol; connections at Delle provide daily services toward Belfort and the Meroux TGV station. Regional MOBIJU buses link Ajoie villages with town, though some services are reduced at quieter times. Check current rail and bus timetables before travel, since engineering work and annual timetable changes can affect connections.
Allow at least half a day for the old town and castle; a full day makes room for the museum, garden or a dinosaur site. The centre is walkable, but the castle sits above it and the Courtedoux trail requires a separate trip. Porrentruy’s appeal lies in the way these layers meet: a former princely seat, a nineteenth-century rail and watchmaking town, a contemporary service centre, and a gateway to a landscape where dinosaur tracks remain visible. Nothing needs an invented Roman foundation to make that story compelling.