Rollin on the River Inline and Cycling Marathon presented by: Register here Welcome to the 9th Annual Rollin’ on the River Inline Marathon in Grand Forks, North Dakota August 24th 7am, 2019. We have three races for you to choose from. A Full Marathon, a Half Marathon and our Annual Family Fun Skate! New this year: a 26.2 Mile Cycling Marathon! Bike the same course as our Inline Skaters!