Horse Rock Ridge Research Natural Area was established in June 1995 to protect the best remaining example of a grassy treeless area. Located in the Coburg Hills between Eugene/Springfield and Crawfordsville, the RNA comprises 377 acres and is managed by the BLM. In 2001, the 62-acre Horse Rock Ridge Preserve (managed by The Nature Conservancy) was established directly adjacent to the RNA. Horse Rock Ridge is recognized for its diversity of plant species, which include Willamette Valley plants as well as plants more often found in the montane zone of the Cascade Range. There are also several species that are normally only found east of the Cascade Range. For more information, please read the Horse Rock Ridge RNA Guidebook.