Prairie Ridge State Natural Area is a 4,101-acre protected grassland landscape in south-central Illinois, spread across scattered parcels in Jasper and Marion counties. Created through land purchases that began in 1961, it grew from efforts to counter the collapse of Illinois prairie and the steep decline of the greater prairie chicken as grasslands were converted to cropland. Managed through a mix of public and private ownership, it supports habitat for endangered, threatened, watch-list, and area-sensitive grassland species. By 2014, it held Illinois's last breeding populations of greater prairie chickens, making it both a refuge and a long-term prairie restoration effort.