I found the various web sites for Corps of Engineers and National Parks, but I'd really like to have a directory of all that I could just download and keep on my laptop rather than having to log into ...
I go to POIFactory and download the csv file of campground for the US. This is then imported to my Streets and Trips and then I have it on my laptop. Doesn't have all the data but does have enough so I can see if I want to look that campground up in the paper copy.