Kieft's War (1643–1645), also known as the Wappinger War, was a conflict between the colonial province of New Netherland and the Wappinger and Lenape Indians in what is now New York and New Jersey. It is named for Director-General of New Netherland Willem Kieft, who had ordered an attack without the approval of his advisory council and against the wishes of the colonists. Dutch colonists attacked Lenape camps and massacred the inhabitants, which encouraged unification among the regional Algonquian tribes against the Dutch and precipitated waves of attacks on both sides. This was one of the earliest conflicts between settlers and Indians in the region. The Dutch West India Company was displeased with Kieft and recalled him, but he died in a shipwreck while returning to the Netherlands; Peter Stuyvesant succeeded him in New Netherland. Numerous Dutch settlers returned to the Netherlands because of the continuing threat from the Algonquians, and growth slowed in the colony.

New Netherland was a 17th-century colonial province of the Dutch Republic located on the east coast of what is now the United States of America. The claimed territories extended from the Delmarva Peninsula to Cape Cod. Settlements were established in what became the states of New York, New Jersey, Delaware, and Connecticut, with small outposts in Pennsylvania and Rhode Island.