The Ultimate Man Lac de Narlay is a trail race held at Camping Lac de Narlay in Le Frasnois, located in the Jura region of Bourgogne-Franche-Comté, France. Typically scheduled for late September, it features a straightforward yet demanding format: participants have one hour to finish a 6.7 km trail loop that includes approximately 185 metres of elevation gain. They then restart the loop at the beginning of the next hour.
The race employs a last-runner-standing format instead of a set distance. Each hourly start sends participants back onto the identical loop. The No Limit option continues until only one runner remains, while the Discovery option concludes after four laps, totaling 26.8 km. The course winds around Lac de Narlay, set within the natural Jura landscape of lakes and ponds, incorporating technical trail sections designed to aid preparation for longer trail events. Participant numbers are limited to around 200, maintaining a small scale compared to large urban endurance races.