It would be nice to be able to find a listing of campground closures.

Are you looking for something like a webpage that tells you which campgrounds in a National Forest are closed due to natural disaster / large maintenance projects or are you looking for a simplified listing of when campgrounds open and close in a national forest?

If it is seasonal information you are looking for, you can find it by looking up the specific campground in the National Forests & Campgrounds portion of this website although I think you are right that a simplified listing for national forest campground seasonal dates would be quicker.

Many of the national forests have that kind of listing in their website.

Thanks for the suggestion!!