Thousands of years ago glaciers covered and moved through this area of Minnesota. Blocks of ice from the glaciers broke off and were covered with rocks, sand and other sediments in what is called glacial till. Some of these ice blocks were pushed underground by the force of the glaciers. Years later when the ice eventually melted, depressions were left in the ground and these sometimes filled with water forming what is known as kettle lakes. How can you tell the difference between a lake and a pond? It is actually hard to find a consensus but in general, it depends on size. If the body of water is larger and deep enough that light doesn’t reach the bottom, then it is usually considered a lake. Ponds in general are smaller, shallower and light reaches the bottom. The northern-western part of Sunfish Lake that is contained in the park is shallower than the southern end, is actually considered wetland. In some years this part has gone dry. There are a number of ponds and small wetlands scattered throughout lower levels of the Park. These may be wet or dry depending on the precipitation pattern.