New Castle, Delaware was originally settled by Swedish peopleSwedes in 1640, followed by the Dutch in 1651, under Peter Stuyvesant on the site of a former Indian village, "Tomakonck" ("Place of the Beaver"). The original name of New Castle was Fort Casimir. This was changed to "Trefaldigheet" ("Trinity") following its capture by the Swedes on Trinity Sunday, 1654. After its recapture by the Dutch the following year, the name was changed to New Amstel. Under Sir Robert Carr, the British routed the Dutch in 1664 and changed the name to New Castle. The Dutch again seized the town in 1673 but it was returned to Great Britain the next year under the Treaty of Westminster. In 1673 it was conveyed to William Penn by the Duke of York and was Penn's landing place when he first set foot on American soil in 1682. This transfer to Penn was contested by Lord Baltimore and the boundary dispute was not resolved until the survey conducted by Mason and Dixon, now famed in history as the Mason-Dixon Line. The spire on top of the Court House--Delaware's Colonial capital and first state house--was used as the center of the The Twelve-Mile Circle12-mile circle forming the northern boundary of Delaware and part of the Mason-Dixon Line which became the dividing mark between Delaware and the slave states of the south and the free states of the north. The area above the Mason-Dixon Line, most of New Castle County, was considered part of the Union, while the southern two counties, Kent and Sussex, considered themselves part of the Confederacy. The Delaware River within this radius to the low water mark on the opposite shore is part of Delaware. Thus the Memorial Bridge was built as an intrastate span by Delaware, without financial participation by neighboring New Jersey. New Castle was the meeting place of all Colonial Assemblies, became the first state capital, and remained a county seat until after the Civil War. Three signers of the Declaration of Independence were from New Castle--Thomas McKean, George Read and George Ross. New Castle was the eastern terminus of the New Castle and Frenchtown Railroad, the second oldest (1852) rail line in the country. It traversed the Delmarva peninsula, running to Elk River, Maryland, from where passengers changed to packet boats for further travel to Baltimore and points south. Source: http://en.wikipedia.org/wiki/New_Castle%2C_Delaware