|We left The Tetons and drove the 17 miles to the entrance of Yellowstone. It was a further 22 miles to the 1st campsite which was full. Then another 16 miles to the next campsite which was also full, and where we discovered that ALL campgrounds were full. I didn't realize how large Yellowstone is. We kept driving north stopping to sightsee along the way. We saw lots of bison, a pack of wolves in the distance, and a herd of elk. We exited the park at the north gate and drove into Montana. It started raining so we were glad for the full hook-up at the RV Park. Especially when the temperature dropped to 39 degrees overnight.