I don't know about all of the USA, but here in Maine we have something similar. Most of the land in New England is privately held (because people settled here s

I don't know about all of the USA, but here in Maine we have something similar. Most of the land in New England is privately held (because people settled here so long ago compared to the west), but people are still more or less free to roam about it. So long as you're actually out in the woods and not chilling in somebody's back yard, you're in the clear. Landowners can prohibit certain uses - hunting, foraging, etc., or even any trespassing - but the default is for land to be open, any restrictions must be clearly posted, and I believe that there are tax incentives for keeping the land open.