Rollin on the River Inline and Cycling Marathon presented by: Welcome to the 10th Annual Rollin’ on the River Inline Marathon in Grand Forks, North Dakota August 22th 7am, 2020. 2020 Registration Now Open! Click here to Register! We have three races for you to choose from. A Full Marathon, a Half Marathon and a 26.2 Mile Cycling Marathon! Bike the same course as our Inline Skaters!