The North Sand Hills is located approximately 10.5 miles north east of Walden, Colorado. From Walden, take Highway 125 north just past the town of Cowdrey. Take a right (east) on County Road 6 to BLM road #2509 (right). Follow the bladed road into the SRMA
Great area, free camping, a lot of trails as well if sand riding isn't your thing. I would definitely recommend that you bring a paddle if you're not used to riding in very soft sand.
I have been riding ATVs there for 30 years while traveling over 400 miles one way to get there. Nice place to camp and ride. Very nice views, elevation about 8500'. Great place if you like sand, pretty clean for a public area with no trash facilities. Always nice to visit Walden, great grocery store and good places to eat. The big weekends can be really busy and rowdy. Sadly it seems that every time I visit every two or three years new areas are closed off by the BLM. There is still a lot of area and trails to ride. I am glad that they are keeping some of the OHV trails to no more than 50". Even though I don't like some of the dunes closed off, I would like to thank who ever did it for improving and repairing some trails, especially around Government creek!
Drove 770 miles (about 12 hours) to ride here. My best advice? Split the difference between the best and worst reviews on here. I think the riding is amazing and would rate the mountain trails as difficult. My wife could ride them but they were not enjoyable to her. If you stay on the low trail on the "mountain side" of government creek, it's easier and a variety of terrain. The dune trails are all whooped out and that gets old pretty quick. The dunes are amazing but if you haven't rode sand before, it's power robbing. As you know, there are closures happening and the maintenance is minimal. The pit toilets are pretty gross. Roads are washboard and the structured campsite area has exposed culverts. Pictures attached. We camped for two nights and the beauty of the stars when the sun fully goes down is amazing! We camped in our uninsulated cargo trailer and froze the first night :-)