The broad Susitna river Valley, including what is now the recreation area, was scoured by massive glaciers, which once covered it. When the ice retreated some 9,000 years ago, it left a rolling landscape of elongated glacial deposits, called drumlins, dotted with hundreds of lakes and ponds.

Through the years, most of the Nancy Lake area has remained wild and natural. The area is too wet for ideal cultivation and is not mineral-rich, so it has escaped large-scale settlement by humans. Today, those assets make it a prime place for recreation and enjoyment of nature.