Ultra-Trail Oise Cosacienne

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.