Miller State Park UFO sighting, 900sqf object hovering above tree line

As my kids and I were leaving the Town of Peterborough by car and going up the last hill next to the entrance of Miller State Park on route 101 we all saw a flying object hovering just above the tree line. At first we thought it was a plane but as it wasn’t moving (only hovering) and was much larger than a drone, we estimate about 900 square feet round, it was something we never had seen before. It’s underside circular shape was accompanied by spaced white lights in a round circle and with one light in the middle of the circular object. As we continued over the hill and past Miller State park entrance my son tried to take pictures while we were driving and he noticed it started to fly quickly away from the left of route 101, where the state park is, to the right side of the road. He said it looked like it followed us for a few seconds and the shot of into the horizon.