Worcester County is the only county in Maryland that borders the Atlantic, the only one bordering both Delaware and Virginia, and the easternmost piece of the state. It was carved out of the much larger Somerset County in 1742 and named for Mary Arundell, wife of Sir John Somerset — himself a son of Henry Somerset, 1st Marquess of Worcester. The county seat moved from a spot near Dividing Creek to Snow Hill, at the head of navigation on the Pocomoke River, where the deepwater port could support a courthouse town. In 1779, Stephen Decatur was born at Sinepuxent, near what is now the town of Berlin - the future U.S. Navy officer who would burn the captured frigate Philadelphia in Tripoli Harbor, become the youngest captain in Navy history, and die in a duel in 1820. Several Worcester County schools still bear his name. Maryland's only Atlantic county produced one of the Navy's most romantic figures within its first generation.

Worcester County had one of Maryland's most unusual antebellum demographics. In the 1840s and 1850s it had the highest proportion of free people of color per capita of any county in the state - a result, the historians argue, of long Quaker and Methodist influence. The county had an active abolitionist movement among the Methodists, Quakers, and Presbyterians, while the slaveholding community was overwhelmingly Baptist and Catholic. First-generation immigrants from England and Germany sided with the Union; first-generation Irish Catholics sided with the Confederacy, and the county's Copperhead movement was led from within the Irish community. The county sent men to both armies. The mixture made for a population whose modern legacy includes deeply Black communities in Snow Hill and Berlin and rural neighborhoods where the surnames have not changed since before the Revolution. Worcester County is more racially complicated than any tourism brochure tries to explain.

The Pocomoke River runs through bald cypress swamps - the only natural cypress stands this far north on the Atlantic coast. In the first half of the nineteenth century, a brick blast furnace at Furnacetown smelted bog iron ore mined from the swamp into pig iron. The community grew to about three hundred people before the furnace closed in 1850, undercut by Pennsylvania anthracite operations. The cypress forests fed shipbuilding at Newtown, later Pocomoke City, and supplied roofing shingles to growers across the mid-Atlantic. The Furnace Town Living Heritage Museum now preserves the ironworks site with an iron furnace, broom maker, blacksmith shop, and church reconstructed on the original footprint. The county's industrial archaeology is unusual because it grew out of swamp - hot iron pulled from cold water, an ecology no one would have designed but settlers learned to read.

Two storms in the twentieth century shaped Worcester County. The 1933 Chesapeake-Potomac Hurricane cut the Ocean City Inlet, transforming the resort. The Ash Wednesday Nor'easter of March 1962 hit even harder. Sustained winds and astronomical high tides drove a four-day storm surge across the barrier islands. On Assateague Island, where speculators had been laying out streets and selling lots, the storm flattened almost every structure. Faced with the cost of repairing infrastructure that the next storm would just destroy, planners gave up on private development. In 1965, Congress established Assateague Island National Seashore. The storm that ruined a real-estate scheme created one of the most accessible wild beaches on the East Coast. The wild Chincoteague ponies, who have lived on the island for centuries, would have lost their dunes to vacation cottages if not for the Nor'easter. Disasters set parks where lobbying could not.

Ocean City was founded in 1875 as a railroad-and-steamer summer resort and stayed seasonal for nearly a century. The post-1960s expansion - which built the boardwalk hotels, the condominiums north of the inlet, and the Coastal Highway that runs ten miles along the island - has turned the northern part of Worcester County into a year-round community. The 2020 census counted 52,460 residents, with a median age of 50.5, second-oldest of any Maryland county. The retirees do not all live in Ocean City; many settle in the planned community of Ocean Pines, on the bayside near Berlin. The county runs from primitive cypress swamp at the south end to high-rise resort at the north, with farming and forest in the middle. The poultry industry, which replaced truck farming after California irrigation opened up, still ships chicken from processing plants here. Spiro Agnew, the Maryland governor who became Richard Nixon's vice president and then resigned in disgrace, retired to Ocean City. He is buried at Dulaney Valley Memorial Gardens in Timonium, but his retirement house is part of the local lore - the higher up the political ladder a Marylander climbs, the more likely they end up on the Worcester County coast at the end.