North Dakota does not require a specific license for snowmobiling. However, you must be at least 10 years-old and possess a snowmobile safety certification card or over 15 years-old and have a valid driver's license to operate a snowmobile in North Dakota. Riders aged 10 or 11 must be under the direct supervision of a parent or guardian.
Check out these Washburn, ND ATV/OHV resources:
