Ultra-Trail Oise Cosacienne
Ultra-trail of Choisy-au-Bac (Oise) — event on hold since 2021
Edition 2026 — event currently on hold
There is no edition scheduled in 2026 for this event. This page remains accessible to archive the history of the manifestation and will be updated if a new edition is announced.
About UTOC
ℹ️ Event currently on hold. The Ultra-Trail Oise Cosacienne has only had one documented edition (June 2021) and no edition has been publicly confirmed since. The organisers indicated in early 2023 that they were giving up on a second edition. As of the verification date, no 2026 edition has been announced by the organiser, nor is it listed in the official agenda of the municipality of Choisy-au-Bac.
Trail running in the heart of the Oise
The Ultra-Trail Oise Cosacienne, better known by its acronym UTOC, is a trail running event that started in Choisy-au-Bac, a commune located at the confluence of the Oise and Aisne rivers, at the gates of the Compiègne forest, around the Compiègne viaduct which gave its symbolic name to the edition ("Les 10 ans du Viaduc").
Four distances for all levels
The UTOC offered four courses adapted to all levels of practice:
- 10 km du Viaduc (approximately 150 m of positive elevation gain): an introductory course accessible to beginners and families.
- 20 km du Viaduc (approximately 600 m of positive elevation gain): an intermediate course through forest trails.
- 55 km (approximately 1,500 m of positive elevation gain): a long trail that crossed the forests and valleys of the Oise.
- 110 km (approximately 3,000 m of positive elevation gain, solo or relay): the flagship event, a true endurance challenge.
Forest landscapes between Oise and Aisne
The UTOC courses crossed landscapes of great diversity: Compiègne national forest, Laigue forest, banks of the Oise and Aisne, Compiègne railway viaduct, forest paths, riverside trails, and undergrowth passages.
A single documented edition
The 2021 edition ("Les 10 ans du Viaduc, 1re édition") took place on June 19 and 20, 2021. Detailed results are available on specialised platforms (Betrail, Adeorun). On January 17, 2023, the official Facebook page "L'UTOC 2023 — 2e édition" announced the decision to forgo organising a second edition that year. Since then, no edition has been publicly confirmed by the organisers.
The AS Cosacienne
The AS Cosacienne, a sports club in Choisy-au-Bac, was associated with the organisation. The club continues to animate local sports life around running, hiking, Nordic walking, and cycling. Its official page announces other events (Run and Bike, Marathon des vins de la Côte Chalonnaise, 24 h d'Eppeville) but does not mention the UTOC among its upcoming events.
UTOC — edition 2026
ℹ️ 2026 edition not confirmed — event currently on hold.
No 2026 edition of the Ultra-Trail Oise Cosacienne has been officially announced by the organization. The only documented edition to date remains that of June 19 and 20, 2021, and the organizers indicated in early 2023 that they would not organize the second edition. If a new edition were to be proposed, this page would be updated.
ℹ️ 2026 edition not confirmed. At the time of verification, no official source confirms the holding of a 2026 edition of the Ultra-Trail Oise Cosacienne. The official agenda of the municipality of Choisy-au-Bac does not mention any trail during this period, and the AS Cosacienne club does not list it among its upcoming events. The event appears to have been on hold since the single edition in June 2021.
Prices UTOC 2026
Practical information — UTOC
ℹ️ Historical information. The elements below correspond to the 2021 edition. As no edition is confirmed to date, this information is subject to change if a new edition were to be organised.
Access
Choisy-au-Bac is located 5 km east of Compiègne.
- By car: From Compiègne, follow the D81 towards Choisy-au-Bac (approximately 10 minutes). From Paris, A1 then direction Compiègne (approximately 1h15).
- By train: Compiègne station (TER from Paris Gare du Nord, approximately 50 minutes), then taxi or shuttle.
Historical starting point
Choisy-au-Bac (Oise), near the Compiègne viaduct.
Historical contact
Organisation email address: [email protected]
AS Cosacienne — as-cosacienne.com
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Where does it take place — UTOC
Choisy-au-Bac
Choisy-au-Bac, 60750 Choisy-au-Bac