National Delaware Day Date in the current year: July 13, 2025

Delaware is a state in the Mid-Atlantic and South Atlantic regions of the United States. It is bordered by Maryland, Pennsylvania, New Jersey, and the Atlantic Ocean. The state was named after Delaware Bay, which in turn was named after Thomas West, 3rd Baron De La Warr, who served as the governor of Virginia. English colonists also named the Native Lenape people living in the area the Delaware people.

Before the arrival of Europeans, the region that is now Delaware was inhabited by the Lenape, Nanticoke, and Susquehanna Indigenous tribes, among others. The first Europeans to establish colonies in the area were the Dutch and the Swedish in the first half of the 17th century. However, these colonies were short-lived. In 1655, the Dutch conquered New Sweden and incorporated it into their colony, New Netherland.

In 1644, the English arrived and established the Delaware Colony, conquering New Netherland and driving the Dutch out. The Dutch briefly retook the colony in 1673 during the Third Anglo-Dutch War but had to relinquish it under the terms of the 1674 Treaty of Westminster, which ended the war.

Delaware was one of the original British colonies in North America, collectively known as the Thirteen Colonies. The other twelve colonies were Connecticut, Georgia, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Pennsylvania, Rhode Island, South Carolina, and Virginia. The governor of Pennsylvania administered Delaware as the “Lower Counties on Delaware”.

In 1776, the Second Continental Congress published the Declaration of Independence and the American Revolutionary War began. During the war, Delaware provided one of the Continental Army’s premier regiments, the Delaware Blues. The only significant battle fought on Delaware soil during the war was the Battle of Cooch’s Bridge on September 3, 1777; it was one by the British. In April 1778, a minor Loyalist insurrection known as the Clow Rebellion occurred on the Delaware side of the Maryland–Delaware border.

On September 3, 1783, representatives of the United States and Great Britain signed the Treaty of Paris, officially ending the American Revolutionary War and recognizing the United States’ independence. At the Constitutional Convention held in Philadelphia in 1787, Delaware was represented by five delegates: Richard Bassett, Gunning Bedford Jr., Jacob Broom, John Dickinson, and George Read. The Constitution was signed on September 17, 1787, and sent to state legislatures for ratification. Delaware became the first state to ratify the Constitution on December 7, 1787, voting unanimously and earning the nickname “the First State”.

In 2017, National Day Calendar launched the National State Days project to recognize the history, culture, and heritage of each state in the order they joined the Union. Since Delaware was the first state to ratify the U.S. Constitution, the cycle of celebrations begins with National Delaware Day, which is celebrated the week after Independence Day.