About 20,000 years ago, the late Wisconsinan glaciation reached its maximum extent. Glacial deposits identify the moraine, or farthest area covered by the glacier. Muddy Creek was a north-flowing stream that was blocked by the south-advancing glacier, forming a huge lake that lasted until the glacier dam began to retreat. The lake rapidly drained, eventually exposing the vast Muddy Creek basin. Dr. Frank Preston envisioned recreating the ancient glacial lake and worked with the Western Pennsylvania Conservancy to begin the project that became 16,725-acre Moraine State Park. Its centerpiece, man-made Lake Arthur and the surrounds, provide outstanding outdoor recreation and relaxation opportunities.