Mt Whitney Zone Forums General Discussion Walk-in campsites - Mosquito Flat & Horseshoe Meadows

I am not sure, but I think there are only a few sites at Mosquito Flat, so it isn't a sure thing there. But in the past, I have slept in or beside my car in the parking lot.

Edit: thanks to Bob's post above, with ten non-reservable one-night spots, it would seem like you should be able to get one of them.