Upper Pines Campground is the largest of Yosemite campgrounds in the Valley, and it's located near Curry Village. It's open all year, but reservations are only required from March 15 through November - the rest of the year is first-come, first served.
You'll find 238 campsites at this campground (RVs are allowed at Upper Pines), and each campsite is equipped with a fire ring, a picnic table, a food locker to protect your food from marauding bears (trust me, they do maraud!), nearby restrooms with flushing toilets, and drinkable water. See more at Discover Northern California: http://tinyurl.com/6gcur48