We went here with our 2 dogs for a quick overnighter-only about 45 minutes outside of Boulder. It was a Sunday morning and the lot was almost full when we got there around 9am. We packed it in and walked the whole trail looking for the best spot and ended up backtracking about half way to a site we saw across the St. Vrain. We crossed the creek by foot and set up right under what we later learned was a mountain lions apartment. We were far enough away from the trail that we were not bothered by day hikers. The stars were AMAZING and the sky was perfectly clear. Lots of firewood around-we brought our hand saw and cut enough feld wood to last until around 4am. We were about to go to bed around 11pm when our dogs started barking. My wife went to quiet them down and when I shined my head lamp toward the tent I saw a mountain lion perched above where we were camping on some rocks about 30 feet away. We yelled and made a lot of racket but it didn’t phase the lion. We threw rocks at it (something we had laughed at when we read about what to do in the event of an encounter) and that got it to slowly walk off into the night. About an hour later it came back and our dogs alerted us again. This time it was closer. We did the same thing-made a lot of noise and threw rocks at it until it went away. We stayed up making noise and being scared until our wood ran out and then passed out in our tent for a few hours until the sun came up. It was a scary experience but the next time we camp here we will stay closer to where everyone else stays at the beginning of the trail. When we got back to our car there was a big dusty bear paw print on our passenger side door. Colorado nature folks!