Assateague Island National Seashore protects most of a 37-mile barrier island on the Maryland and Virginia coast, along with nearby marshes, waters, and a mainland visitor center. Established in 1965 after the Ash Wednesday Storm of 1962 ruined a planned resort development, it preserves the Middle Atlantic states’ largest predominantly undeveloped barrier-island ecosystem. Assateague is shaped by constant change, as storms, overwash, longshore drift, and sea-level rise steadily move the island westward. Its beaches, dunes, marshes, and woodlands support important bird habitat and free-roaming horse herds, while the seashore today balances conservation with recreation across this unusually intact Atlantic landscape.