I was going to recommend Ultimate Campgrounds, but now when I try to open the link, it comes up with the message :you do not have access to this page!
It listed lots of campgrounds, but I don't know what has happened to it. Or if it's just temporary and will be back soon.
It used to be free on a computer, but I do know that it was a paid app on mobile devices. But when I search the app store on my phone, nothing comes up for it.
EDIT: Here's the answer:
Time marches on. We cannot always keep up, however, and sadly that applies to Ultimate Campgrounds. After 14 years we have come to the end of the road.
However, we are pleased to announce that our carefully-cultivated database of over 46,500 locations is being taken over by the folks at Garmin®. For several years Ultimate Campgrounds has been featured in a number of their GPS systems and is now being added to the Garmin® Tread™ app.
Although our apps have been discontinued in the app stores, folks that already have the app can continue to use it for as long as they like. Just be aware that over time the data will slowly become less up-to-date.
Our FAQ page will remain active for any users that may have a question.
Bill, Geoff and Ted all thank you for your continued support and contributions over the past 14 years and we hope we have helped you find some great places to pitch your tent or park your RV.
The UC Facebook page will live on; Ted will continue to post items of interest that he comes across.