I have plans to go to J Tree at thanksgiving and have campsites reserved except for the night of Friday 23rd. Any idea how early I'll have to get there for a first-come-first-served site? i.e. if I get there on Wednesday morning, will I be able to grab a site for 4 nights? What about Thursday morning (for 3 nights)?

Actually, I don't really know how the FCFS sites work. What's the limit on the duration you can reserve? Can I turn up and keep a site for 5 days? 10 days? or do I have to pay each day? nps.gov and recreation.gov aren't particularly clear on this point

You can pay up front for as many nights as you intend to stay, up to the 14 day limit. Show up in the campground early in the AM (like sunrise), walk through the campground and look for people who appear to be packing up to leave. If they are leaving, ask if you can have the site. If nobody else has asked first, it's yours.

Some people might be willing to let you share their site for a few days, in which case you should contribute part of the cost of the site.

The "campground full" sign at the entrance to Hidden Valley Campground is more or less a permanent fixture from October through late April. Don't let it stop you, there are sites changing hands just about every morning.

I would expect a lot of competition for campsites on the Wednesday before Thanksgiving.

So do you pay at the rangers station at the entrance to the park (along with your entry fees)? And does this mean that paying (up front) doesn't guarantee you a site? That is, do they keep track of how many people are (in principle) in the camp grounds at any one time?

Nick,

At both the Joshua Tree and Twentynine Palms entrance to the park, there are Visitor Centers manned by the NPS. They can answer your questions.

Additionally, you can visit this website or call them with questions:

www.nps.gov/jotr/planyourvisit/camping.htm

1) Before entering a campsite area, grap a camp fee/res manila packet (about 3x5 inches or so), and bring it with you as you look for a site. This will ensure that when you find a site, if others are looking as well, you are ready to claim it and not dilly dally about.

2) Double check the previous res card to make sure the previous group has left/is leaving that day (if there is one on the camp post).

3) Place $$$ ($5 per night, I believe) in envelope, keeping your stub.

4) Place your stub with desired dates (no need to check with rangers; it's FCFS) -- I believe max days at one site is 14 days -- on camp post.

5) Place envelope in "iron ranger" at front of campground.

6) Shred the gnar in the park

Campsites are now $10/night.

Nick, paying for the campsite is self-service, at the campground. Like Wagreich says, there's a stack of fee envelopes at the entrance, and a metal post (the "iron ranger") that serves as a drop box for the envelope with your money in it.

Relax, you'll probably find a site.

Thanks for the helpful replies everyone!