New Castle Court House Museum

The New Castle Court House is Delaware's oldest surviving courthouse and one of the most historically significant colonial buildings on the East Coast. Built in 1732 on the foundations of an earlier structure, it served as the colonial capital's principal government building — here, the colonial assembly met, land grants were recorded, and justice was administered under three different flags before American independence.

The building is now a museum operated by the Delaware Division of Historical and Cultural Affairs. The ground floor has been restored to its colonial appearance, with exhibits explaining the building's role in Delaware's colonial government and the famous Twelve-Mile Circle boundary. Guided tours are available. The courthouse faces the Green, the historic town square laid out in the Dutch period, and the juxtaposition of the two — courthouse, green, and church — gives New Castle its particularly photogenic historic center.

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A story
The cupola of the courthouse was the center of one of the most unusual borders in North America. In 1701, the Crown granted the three lower counties of Penn's colony a circle of land with a 12-mile radius from this building — the famous Twelve-Mile Circle that still forms most of Delaware's northern boundary with Pennsylvania. No other U.S. state boundary is drawn as an arc from a single point.