$20 per night, level paved spots with shelters, picnic tables, and fire rings. Totally worth paying for the campsite if you want to explore the area and not worry about finding a spot later in the day. Had a buffalo right near the camp spot I was at! Apparently it's bug season so beware. And wind season. Watched sunset from the van due to wind.

Agree totally worth paying for the site if you are exploring Antelope Island. Day fee is $15 which they subtract from your campsite reservation (which I believe is now $30). There are great mountain bike trails right from the campground, bathroom facilities with showers, and stunning sunset views over the lake from every site. Not crowded on a Monday night in June.