The Stillwater 500 is a 500 acre park for dirt bikes, ATV's and bicycles.  The park is leased  by the city of Stillwater and the Stillwater Trailriders maintian the park.  A use permit is required for all persons who ride at the park.  Permits are $75.00 and good for 1 year from time of purchase.  One permit is good for 2 adults and 2 children under age 18.  When you purchase your permit you will receive in the mail 2 decals that should be placed on your helmet and a plastic permit tag that hangs on you rear view mirror of your vehicle.  The park is patrolled by the Stillwater Police department via ATV.  If you are caught on the property without a permit, you will be subject to a fine.