New Castle Court House Museum

Where Delaware Was Born

The Building Where Delaware Declared Its Independence and Became America’s First State — Free to Visit

There is one building in Delaware more constitutionally significant than any other: the New Castle Court House, built in 1732, which served as the colony’s — and then the state’s — first court and seat of government. It was here that Delaware’s General Assembly met, colonial law was administered, and on September 20, 1787, Delaware voted to ratify the United States Constitution — becoming the first state to do so and earning the nickname “The First State” that Delawareans still wear with quiet pride. The name is literally a fact, and it happened in this building.

The New Castle Court House Museum is part of the First State National Historical Park, operated by the National Park Service. Admission is free.

The museum is open Tuesday through Sunday, 9:00 a.m.–5:00 p.m. The museum is closed Monday.

Always confirm current hours at nps.gov/fone before visiting, as NPS sites occasionally adjust hours seasonally or for special events. On-street parking is available throughout Historic New Castle.

The History of the Court House and Delaware’s Founding

The New Castle Court House was built in 1732 on land that had already been the center of governance in the Delaware Valley for nearly a century. The site traces back to the Swedish, Dutch, and English colonial administrations that successively governed New Castle — Delaware’s oldest continuously occupied town — from the 1630s onward.

Colonial Government

When the Court House was completed in 1732, it immediately became the most important public building in the colony. It housed the court system, the colonial assembly, the county government, and the full administrative apparatus of colonial Delaware. The building’s cupola served as the center point from which the famous “Twelve Mile Circle” — the boundary between Delaware and Pennsylvania — was originally measured. That circle, drawn with New Castle’s Court House steeple as its center, is one of the most geometrically unusual state boundaries in the United States, and its origins are entirely traceable to this building.

The Revolution and Delaware’s Ratification

As tensions with Britain intensified through the 1770s, the New Castle Court House became a gathering place for Delaware’s revolutionary deliberations. The Assembly met here through the critical years leading to independence. When the Declaration of Independence was approved in Philadelphia in July 1776, Delaware delegates Caesar Rodney, George Read Sr., and Thomas McKean cast their colony’s vote — a vote that followed deliberations and preparations that took place in and around this building.

The most constitutionally decisive moment came on September 20, 1787, when Delaware’s convention voted unanimously to ratify the United States Constitution — 11 days before Pennsylvania and 16 days before New Jersey. Delaware’s speed and unanimity reflected both the state’s confidence in the new framework and the organizational effectiveness of its leadership. The “First State” title, earned in this building, has defined Delaware’s identity for 235 years.

Trivia: The Twelve Mile Circle — the arc that forms Delaware’s northern boundary with Pennsylvania — is the only circular state boundary in the United States. Drawn with a compass centered on the New Castle Court House cupola, it was established by a 1681 grant from King Charles II and has been a source of legal and surveying disputes ever since.

What to See and Experience

Museum Galleries

The Court House’s interpretive galleries cover Delaware’s history from the colonial period through the early national era, with exhibits on:

• The colony’s courts and General Assembly — how colonial governance actually functioned in the building
• The social and cultural history of colonial New Castle — daily life, commerce, and community
• Archaeological evidence from the site and the surrounding historic district
• The Underground Railroad history is connected to New Castle — the town’s position on the Delaware River made it a complex site in the story of freedom-seeking in the antebellum era
• Period portraits, furniture, artifacts, and decorative arts from the 18th and early 19th centuries

Orientation Film

A narrated orientation film provides an overview of the building’s history and architecture — narrated by Ed Asner in the version available at the nearby New Castle Visitor Center at The Arsenal, which serves as the starting point for visitors to the historic district. Guided and walking tours of the historic district also depart from the Arsenal.

The Building Itself

The Court House is one of the finest surviving examples of 18th-century public architecture in Delaware. Its proportions, brickwork, and cupola are characteristic of the Georgian public buildings of the British colonial period — designed to project authority, stability, and the dignity of law. Walking through the restored interior, visitors encounter spaces that have functioned continuously as part of Delaware’s public life for nearly 300 years.

First State National Historical Park

The New Castle Court House Museum is one of several sites that together form the First State National Historical Park, which was established by Congress in 2013 to preserve and interpret Delaware’s role in the founding of the United States. The park encompasses sites in New Castle, Dover, and other Delaware locations — collectively telling the story of Delaware’s distinct identity within the American founding narrative.

Other First State NHP sites in New Castle and Wilmington include Old Swedes Church (Holy Trinity) and several sites within the New Castle Historic District. Together they form a walking itinerary through 400 years of documented Delaware history — from the 1638 Swedish landing to the 1787 Constitutional ratification — in a remarkably small geographic area.

New Castle Court House in the Historic New Castle District

The Court House anchors the New Castle Historic District’s central green — a cobblestone square that also contains the Old Library Museum/New Castle Historical Society, the Visitor Center at The Arsenal, and direct access to the broader historic district that extends along The Strand to the Delaware River. The Read House & Gardens, the Dutch House Museum, and the Amstel House Museum are all within a five-minute walk. The entire district is walkable in an afternoon, free to explore on foot, and consistently described by visitors as one of the most authentic and least-touristy colonial American environments accessible in the mid-Atlantic.