Evening sunset light bathes showy evening primrose in prairie grasses at the 10,894-acre Tallgrass Prairie National Preserve in the Flint Hills of Kansas in Chase County near the towns of Strong City and Cottonwood Falls. Less than four percent of the original 140 million acres of tallgrass prairie remains in North America. Most of the remaining tallgrass prairie is in the Flint Hills in Kansas. Tallgrass Prairie National Preserve is the only unit of the National Park Service dedicated to the preservation of the tallgrass prairie ecosystem. The Tallgrass Prairie National Preserve is co-managed with The Nature Conservancy.