At about 3.79 million square miles, the United States is a vast nation – the world’s third largest by land area. The diversity of our terrain provides off-road riders with an all-you-can-eat buffet of ATV riding choices available for the taking -deserts and dunes of the southwest, towering peaks in the Rocky Mountains, dense forests and the countless lakes of the Midwest, stunning views from atop the Ozark Mountains and the colossal riding areas of the rolling Appalachians.If you live in the Western United States or want to travel out there for a change in your ATV riding terrain, here are six great spots in the Pacific U.S. region to get you started.Imperial Sand DunesPerhaps the most famous off-road destination in the country, and one of the most popular ATV riding areas in the world, the Imperial Sand Dunes (frequently called Glamis) of Southern California near the Mexican border includes approximately 118,000 acres for off-highway vehicles like ATVs, dirt bikes, sand rails, side-by-sides and trucks.Riding the Imperial dunes for the first time is daunting, with difficulty ranging from easy to white knuckles. Getting lost is a concern, as the terrain is always morphing, and the scenery blends together. The payoff is riding in an endless desert paradise seemingly designed exclusively as a high-speed ATV riding oasis.Mojave DesertA spectacular getaway for residents of the Southwest, and anyone looking for a change of pace, the Mojave Desert in California contains some of the greatest high desert riding in the country. Terrain varies from enormous valley stretches to mostly treeless hillsides that bring riders thousands of feet above the desert floor. Don’t let the extreme weather scare you off. Springtime in the Mojave is particularly delightful, as the desert is bursting with life and blanketed by bright patches of wildflowers.Mount Hood National Forest There’s a reason you periodically hear of exploring hikers trapped on Mount Hood in Oregon – the view and extreme high-altitude experience is worth a little risk. If you go by atv and stay on the marked trail system, you can get a similar thrill without having to pack and carry camping gear, and you’ll probably make it out alive at the end of the day.Mount Hood is incredibly beautiful, and the above-the-clouds (in some cases) ATV trails offer riders great variety and make for a very amusing and scenic ride. This is dream-like riding on a grand scale.Oceano Dunes State Vehicular Recreation AreaLocated along the beautiful Pacific coast in Southern California just north of Santa Barbara, Pismo Beach’s Oceano Dunes State Vehicular Recreation Area is a popular ATV destination for sand dune riding right on the ocean coast. Formerly known as the Pismo Dunes, Oceano is a geologically unique location. The prevailing ocean winds create uncommon riding conditions, but all riders must exercise extreme caution in spotting dangerous slipface drop-offs.Ocotillo Wells State Vehicular Recreation AreaAs California’s largest State Vehicular Recreation Area (SVRA), Ocotillo Wells has more than 80,000 acres of desert that’s open to off-highway exploration, which is a gargantuan amount of riding possibilities. Even better, Ocotillo is affordable: no fees are collected for camping or day use, and camping is permitted for up to 30 days a year – so stay a while!Key attractions include the eroded Blow Sand Hill, the 200-foot-high Devil’s Slide, Barrel Springs sand dunes, the unusual Shell Reef and Pumpkin Patch sandstone concretions.Oregon Dunes National Recreation AreaLike no other place on the planet, the Oregon Dunes bring fantastic dune riding, the Pacific Ocean and pine trees together in one remarkable spot. The dunes start at the sea and, at points, stretch two miles inland and reach up to 500 feet above sea level.The continent’s largest expanse of coastal sand dunes, approximately half of the Oregon Dunes are open to motorized vehicles. Campgrounds, staging areas and several annual events make this a top ATV destination.