This IBA includes a 100km length of the Chesapeake and Ohio Canal National Historic Park between the DC Beltway in Montgomery County and Antietam in Washington County, and several adjacent parks and natural areas including Blockhouse Point Conservation Park, the lower portion of Seneca Creek State Park and McKee-Beshers Wildlife Management Area. Floodplain forest lies along much of the canal and also in extensive parts of McKee-Beshers WMA, which contains fields managed for game species. Most of the remainder of the site consists of upland deciduous forest with streams. The entire IBA is in various kinds of public ownership. C & O Canal National Historic Park is owned by the National Parks Service, McKee-Beshers WMA and Seneca Creek SP is owned by Maryland DNR, and Blockhouse Point Conservation Park is owned by Maryland ? National Capital Park and Planning Commission. The Appalachian Trail crosses the site at Harpers Ferry.
Two at-risk species nest along the length of this portion of the C & O Canal. Bird Blitz surveys in the breeding season of 2007 counted 53 Louisiana Waterthrushes and more than 90 Prothonotary Warblers along 58km of the canal towpath and at McKee-Beshers WMA and Seneca Creek State Park. Another species at risk, Rusty Blackbird, occurs at McKee-Beshers WMA during winter and spring and fall migration in flocks often exceeding 100 individuals, a significant number for this once abundant but fast declining species.