New Sweden (Swedish: Nya Sverige, Finnish: Uusi Ruotsi, Latin: Nova Svecia) was a Swedish colony along the lower reaches of the Delaware River in North America from 1638 to 1655; established in the last decade of the devastating Thirty Years' War while Sweden was a very significant Northern European military power. New Sweden was one part of Swedish colonization efforts in the Americas.

The settlements were scattered on either shore of the Delaware Valley in the present-day American Mid-Atlantic states of Delaware, New Jersey, and Pennsylvania, often in places where Swedish traders had been visiting since about 1610.Fort Christina the first settlement, named after the reigning Swedish monarch, the sole daughter of Gustavus Adolphus the Great (Swedish: Gustav Adolf den store, Latin: Gustavus Adolphus Magnus), is now part of Wilmington, Delaware. Along with Swedes and Finns, a number of the settlers were Dutch. New Sweden was conquered by the Dutch in 1655, during the Second Northern War, and incorporated into the Dutch colonies of New Netherlands.