Origins -- Canals and Commerce -- The Colonial Frontier -- Antietam : The Bloodiest Day -- Harpers Ferry -- The Piedmont -- Great Falls -- The Clara Barton Parkway -- The GW Parkway -- Washington and the Potomac -- Anacostia : The Forgotten River -- Plantations on the Potomac -- The Civil War on the Lower Potomac -- The Northern Neck -- The Piscataway Nation -- Catholic Beginnings at the River's End.