The National Ultra Endurance Series (NUE) is an ultra-endurance mountain bike race series in the United States. It was established in 2006 in order to bring national visibility to ultra-endurance mountain bike racing.
The number of races has varied from year to year. Each of the races is approximately 100 miles (160 km) long and primarily off-road. The title of series champion is awarded to the racer with the four best results in each of the following categories: Men's Open, Women's Open, Men's Masters (age 50+), and Single speed. Any ties are broken by the placing results in the final race of the series.
In the past there were requirements to finish at least one race West of the Mississippi River and one race East of the Mississippi. That requirement has been dropped. The list below includes those races that will be in the 2017 series. Some of these races were run before joining the NUE series.
The series used to include the following events: