sentences:  It includes the major cities of Boston, Providence, Hartford, New York City, Philadelphia, Baltimore, and Washington, D.C., along with their metropolitan areas and suburbs.It is sometimes defined to include smaller urban agglomerations beyond this, such as Richmond and Norfolk, Virginia to the south, Portland, Maine, to the north, and Harrisburg, Pennsylvania, to the west.The megalopolis extends in a roughly straight line along a section of U.S. Route 1.