Mariposa Fairgrounds

The Fairgrounds are easy to find, and when we camped here on a Saturday in April 2016, we had plenty spots to choose from. The site we choose was not very level, so bring your leveling blocks. We stayed on a grassy field, I am not sure what it will look like in the summer.
Hookups are electric only, but water is available on the Fairgrounds.
There is a check out time, but not a check in time, which is great when you arrive early! You can just self register. The California State Mining and Mineral Museum is at the Fairgrounds, well worth a visit.
As it is reasonably close to Yosemite, it is a good and affordable spot to stay for a little longer. Unfortunately we had to go back home to our jobs after the weekend. We did visit Hornitos on our way back, a really cool little ghost town nearby.

Good place that has water and electric. They have 5 parking lots. The "nicest" one in grass is on the road, so it does get some road noise. The others are all gravel. If you can't get in to Yosemite, I think this will do for a few day trips in. Nav says it's 1 hr and 20 minutes to Yosemite Valley. $45 per night, $5 per pet

Stayed in April 2021. Convenient to Yosemite, would be even more convenient with the shuttle but it wasn't running when I was there. Showers are wonderful, warm and clean. Sites are nothing special but do the job.

We stayed here while we visited Yosemite. It was one of the few places to stay within an hour of the park. It was self check-in. Fill out the envelope with your credit card information and put it in the slot. The price was stated as $50 a night, but then they nickel and dimed us. $5 extra per pet and $4 per extra person over 3 people. Really?
We stayed in the front, fenced, grassy lot. The lot was not level, but easy enough to level with enough blocks in the rear. It was not full hookup. We had water and electric. The dump station was nearby. The dump station was in a sloped, gravel area and we had trouble pulling out. Had to get a running start, don't stop, to get up the slope and out the gate and off the gravel road.
The sump pump truck came by at 6:30am one morning and began sucking out the septic system. Way too early for that kind of noise!
We were visiting a week and a half before the Labor Day fair. We were told the last day to stay was the 28th so that workers could have time to set up. The workers started showing up early the day before and wanted to get started but of course we had another day. They were confused as to why the fairgrounds were allowing us to be in their spot.
For a few overnights Mariposa was fine, but it was way overpriced for what you get. The only saving grace was the proximity to Yosemite. Starlink worked fine. Verizon and AT&T were fine as well with our cell antenna. We camped at Mariposa Fairgrounds in a Fifth Wheel.