There are two fantastic places to go to hike, swim, picnic, etc. The first is Lake Elmo Park Reserve. It is about 30 minutes from Stillwater.
Camping in tents and RVs is permitted and the camping facilities are top-notch. I'm not sure about the fee. Admission to the park is $5, I believe. You can also buy passes for longer amounts of time. We always bought a yearly pass.
During the summer, activities abound. There are volleyball courts, hiking trails and paved bike (inline skate - hilly) paths. The playground equipment is new and divided equally between the tots and the older children. The highlight, though, is the swimming area. It is unique!
It is a man-made lake, well, sort of. It is difficult to explain. The water is chemically-treated much like a swimming pool and drained at the end of the season. It is more like a lake in regards to the size, shape, and texture (sand). Concession stands, bathroom (changing) rooms, and showers are available. Lifeguards are on duty.
This is a FAVORITE place of mine! I spent many summers here with my babysitting charges. We would pack a picnic lunch and enjoy the sunshine! People are VERY friendly, too.
The second park is Interstate Park. It straddles the St. Croix River, which in turn divides the states of Minnesota and Wisconsin. On the Minnesota side is the town of Taylors Falls. On the Wisconsin side is the town of St. Croix Falls.
I often go here alone to meditate and enjoy some peace and quiet. I pack a picnic lunch and climb to some out-of-the-way boulder and bask in the sun.
Hiking is a favorite activity here and so was cliffdiving up until a few years ago when it was banned. The river itself is home to paddlewheels, canoes, kayaks, and small fishing boats. Camping is allowed with a permit.
Near this park, is Fawn-doe-rosa (sp?) It is a great place to take the little ones. It is a petting zoo. The animals are in their natural habits, some are in cages. I am not fond of zoos due to the whole animal cruelty issue but this zoo is different. The animals housed are abandoned pets, injured animals or animals that for one reason or another cannot survive in the wild. Those injured, once healed, are released back into the wild.