Delaware Colony was a British colony in North America. The area had first been colonized as New Sweden in 1638 and been taken over by the Dutch colony of New Netherland in 1655. English control began in 1664 and the "three lower counties" of Delaware were transferred to William Penn's grant in 1682. Delaware Colony was separated from Pennsylvania Colony in 1704; however, it did not have its own governor. It was named for Thomas West, the Lord de la Warr, an early governor of Virginia Colony.

Delaware colony was one of the Middle Colonies. It was composed of New Castle County, Kent County, and Sussex County, the same three counties that today make up the United States' second-smallest state.

During the American Revolution the colony declared independence and became the U.S. state of Delaware. The state was the first to ratify the United States Constitution on December 7, 1787. In 1792 Delaware wrote its first constitution.