Dishman Hills is a protected natural area along the south side of Spokane Valley in eastern Washington, valued for both its geology and biodiversity. Granite outcrops formed about 70 million years ago, and the Missoula Floods reshaped the terrain around 17,000 years ago into rugged hills marked by potholes, gullies, ravines, and exposed stone. Where forest, grassland, and shrubland meet across two ecoregions, the area supports varied plant and animal life. Modern conservation began in 1966 with local efforts to protect the hills from development, leading to Washington’s oldest land trust and a cooperative preserve that remains open for recreation, education, and wildlife habitat.