Green Lakes became a State Park in 1928 when the state purchased 500 acres surrounding and including two glacial lakes. Through purchase of additional lands, the park has increased to its present size of 1,700 acres. In 1975, the state acquired 188 acres at the southern boundary, which included the drainage basin of round lake. This acquisition was necessary to protect the unique characteristics of the lake. In 1995,  the Betsy Knapp estate donated land known as the "Indian Ovens" to the park. The following year, the state purchased two additional parcels of land, adding nearly 25% to the size of the park. All the land we now know as Green Lakes State Park was part of the so-called military tract, land which was surveyed in 1792 and divided into lots for compensation to the soldiers of the Revolutionary War. Much of the land surrounding the lakes was settled by David Collin the III in 1817, and later divided among his six children. For more then a century - until the establishment of the park - the property remained in the Collin family. Two descendants continue to own property adjacent to the park.    information above taken from park brochure