Trail de la ligne rouge - La 14-18

The Trail de la ligne rouge is a multi-distance nature trail held around Thiescourt and run in parallel with the Ultratrail de la ligne rouge under the La 14-18 branding. Distances offered for 2026 include 10 km, 20 km, 40 km and a 100 km ultratrail (solo and relay formats), each running on predominantly grassy and marshy terrain that recalls First World War trench landscapes. The course follows sections of the proposed GRP route tied to the historical "ligne rouge" and is presented as a flat-to-rolling cross-country trail rather than an obstacle race.

The organiser presents the event as a weekend trail meeting connecting longer ultratrail concepts with shorter companion races, with race starts from Thiescourt (Place du village de Thiescourt for shorter distances). Registration for the 2026 edition opens on 31 October 2025 at 20:00 local time according to the organiser pages. Note: some official pages show a date discrepancy (header 17 May 2026 vs body text referencing Sunday 18 May); the published start date used here follows the event headers and multiple official listings.