Osprey Wilds Environmental Learning Center (ELC), formerly Audubon Center of the North Woods (ACNW), on Grindstone Lake near Sandstone, Minnesota, is a non-profit residential environmental learning center, wildlife rehabilitation facility, and conference/retreat facility.
Located about west of Sandstone, the Osprey Wilds ELC provides environmental education about the various renewable energy systems that it uses, including geothermal heating and cooling (ground source heat pumps), wind generators, biodiesel-powered vehicles which run on used vegetable oil, and grid-connected solar arrays. The ELC includes over of hiking and cross-country ski trails through a variety of habitats, such as old-growth red and white pines, hardwood forests, restored wetlands and prairies.
On December 30, 2021, Osprey Wilds completed the acquisition of the Blacklock Nature Sanctuary in Moose Lake, MN, located 30 miles north of the main Sandstone campus. The Blacklock property was a gift of 414 acres by Craig and Honey Blacklock. The purchase of additional property adjoining the sanctuary east of Moose Lake added another 148 acres to the acquisition. Both the Sandstone and Moose Lake (Blacklock) campuses include property that is protected by conservation easements through the Minnesota Land Trust.