The herbarium of Chesapeake and Ohio Canal National Historical Park (CHOH) was formally established and organized in 2025. Collections include botanical surveys from researchers and collections from National Park Service personnel. All specimens from the herbarium were collected within the legislative boundary of C&O Canal National Historical Park, an area of 184.5 miles along the Potomac River between Cumberland, MD and Washington DC. The focus of this herbarium is to demonstrate the diverse floral resources of the park to the public, with a special emphasis on state rare, threatened, and endangered plant species. The CHOH Herbarium functions as a reference collection of herbarium specimens which supports taxonomic, systematic, biogeographic, ecological, and conservation biological research.