Had a great stay at this KOA. Was busy because of holiday weekend (expected), but didn't feel over run with people. Kids LOVED having the pool, and the playground was big. Very family friendly campground. Only complaints would be that the showers really needed to be cleaned twice a day with so many people using them that weekend- they were quite dirty, and that the ice cream stand was never open, even during a holiday weekend. BBQ dinner and breakfast were very good, store was well stocked, and loved the cement pad and swing in the deluxe site.
We really enjoyed our stay at this campground. Loved that it was off the main road and away from the crowds of Island Park. It was only 10 minutes from W.Yellowstone (w/no construction), which made it a great base camp. There was a nice walking path around the campground for pets and just a short hike over the hill to Henry's Lake. The ONLY bad thing we experienced was the gigantic mosquitoes! Take your bug spray!
This was our first time camping in our trailer, so we used the reviews on this site to select this campground, and we are so glad we did! Our site (#40) backed right up to GSM, which was beautiful. The staff was SO friendly and helpful, and even loaned us some tools. The showers and bathrooms were spotless, as were the campsites. Great location for the surrounding sites. The only thing that didn't work for us was the dog run area. It was pretty small and our yellow lab jumped right over the fence. Overall it was a GREAT place to camp.