Amarillo Area Camping

What’s the beta here? Driving through and don’t have the ability to sleep in my vehicle and I’d prefer not to venture too far off of i40. Any help is appreciated! 

Palo Duro Canyon State park, though I believe it's a reservation system to get a site there. Just outside the gate to the state park, there's a funky private campground where I'm sure you could crash for the night and nobody would notice. As far as free, dispersed dirtbag camping near I-40, it's all stealth out in those parts. Not much public land. But lots of empty dirt roads through fields that you could probably get away with for a night by arriving late and leaving early.