Green Lakes State Park's outstanding features are its two glacial lakes surrounded by upland forest. Both Round and Green Lakes are meromictic lakes, which means that there is no fall and spring mixing of surface and bottom waters. Such lakes have a high potential for evidence of ancient plant and animal life. Another special feature of the park is an 18-hole golf course designed by Robert Trent Jones, where visitors can snowshoe in winter, and there are 10 miles of trails that cross-country skiers can use.