http://www.atvam.org/ ATV Association of Minnesota (ATVAM)
http://www.dnr.state.mn.us/ohv/gps.html OHV Trails Downloadable GPS Data
http://www.dnr.state.mn.us/ohv/index.html OHV riding in Minnesota(everything that you ever want to now about OHV in Minnesota)
http://www.dnr.state.mn.us/ohv/az.html listing of state off-highway vehicle trails for ATV
http://www.nohvcc.org/ National Off-Highway Vehicle Conservation Council