Arizona has several national forests and a good number of federally managed lands that allow the riding of ATVs. The Apache-Sitgreaves National Forest is a jewel of a ride with its easy trails and rolling lush hills. The Coronado National Forest, Coconino National Forest and Kaibab National Forest all have easy, well-marked trails and even beginning ATVers won't have a problem following the trail systems or maneuvering their vehicles on the ATV trails. These are great places for learning to handle your ATV "out on the trail". A good rule of thumb if you're riding with people new to trail riding is to wait until the person behind you had caught up before moving forward across a stream or creek or other barrier. This will insure everyone stays together on the trail ride.
For a more challenging ride and unrestricted ATV fun, check out Copper Basin Dunes OHV Area. This area has a parking area and unloading ramp. There are also bathroom facilities. Your ATV must have the proper sticker and it must be in a prominently visible place on your ATV.
Crossroads OHV Area is a great place to bring your family or ATVing group for a long weekend of riding and having fun. The land surrounds Lake Havasu and there are trails that go around the Lake area. If you're looking to make a long weekend out of staying here. Over 90 campground areas line the shore and there are two public campgrounds, Empire Landing and Crossroads to choose from. The public campgrounds have dump stations, swimming beaches, showers and restroom facilities. There is a 14-day stay limit.
Hot Well Dunes Recreation Area is another fun destination. The sands in this area were actually surrounding a lake roughly 2 million years ago. The remains of that now dried up lake are the sands found here and you can have a blast riding your ATV on the dunes. There are also hot tubs to relax in when you're done riding your ATV for the day.