From the sandstone ridges and shale valleys of western Maryland to the sand dunes and tidal estuaries on Delaware's coast, the geologic features of the Mid-Atlantic region include a diverse array of rocks and landforms assembled during more than 1 billion years of geologic history. The book's introduction presents an overview of the geologic history of Maryland, Delaware, and Washington, D.C., and 35 road guides discuss the landforms and rocks visible from a car window, along bike paths, and at nearby waysides and parks, including Chesapeake & Ohio Canal National Historic Park, Assateague Island National Seashore, Rock Creek Park, and Cape Henlopen State Park.