Southern Maryland is made up of a collection of peninsulas covered in low rolling hills, fields, forests, swamps, and waterways leading to the Potomac River and the Chesapeake Bay. As such, this area enjoyed relative isolation and small population for over three centuries despite its proximity to cities such as Alexandria, Annapolis, Baltimore, and Washington. Those who did settle here developed a close connection to its farms, waterways, and natural remoteness. Southern Maryland, known for the state's earliest Colonial settlements, is composed of three of the state's oldest counties: St. Mary's, Charles, and Calvert. Although largely agricultural and maritime in outlook, this region was also the birthplace of the nation's ideal of religious freedom and many of its greatest citizens, including leaders of the Revolution, the early national government, and the state. Many of their homes and churches survive as historic landmarks, or their existence has been documented and preserved for posterity.