In 1682, James, the Duke of York gave William Penn a deed for land consisting of a 12-mile circle around the town of New Castle.

The borders established by this deed were almost immediately contested by Lord Baltimore, proprietor of the colony of Maryland, and thus began an 87-year legal struggle between the two families.

The final survey of the borders as part of the boundary dispute was conducted in 1763 by Charles Mason and Jeremiah Dixon, who ran a series of chains on a straight 12-mile line from the Court House.

Wirt's conclusion, based on a report by George Read Jr. and former Attorney General Caesar A. Rodney was that the state of Delaware had the valid claim.

[6] After conflicting opinions from two different circuit courts on the issue, President James K. Polk intervened in 1847 and suggested an arbitrator resolve the disagreement.

In addition to the routine passing of laws, Penn's primary focus during the 1700 session was healing a rift that had developed between the assemblymen from Pennsylvania proper and those from Delaware.

[11] In 1774, the assembly met here and chose three of Delaware's most famous politicians to represent the colony in the Continental Congress: Thomas McKean, Caesar Rodney, and George Read.

It was in this building that the assembly, at McKean's urging, voted on June 13, 1776 to sever all ties with England as well as the state of Pennsylvania, with which Delaware still shared a governor.

Resolved unanimously, that all persons holding any office, civil or military, in this colony, on the 13 day of June instant, may and shall continue to execute the same, in the name of the government of the Counties of New Castle, Kent, and Sussex Upon Delaware, as they used legally to exercise it in the name of the King, until a new government shall be formed, agreeable to the resolution of Congress of 15 May instant.When the Congress issued the Declaration of Independence, it was read to the citizens of the town from the balcony on the second floor.

Later in 1776, Delaware's first Constitution was drafted and adopted by a convention including Read, McKean, and Nicholas Van Dyke inside the Court House.

The House alleged that Chase had been engaged in a witch hunt to silence Democratic opposition, and that he had abused his authority by refusing to release the grand jury in New Castle.

The article of impeachment stated that Chase, "did descend from the dignity of a judge and stoop to the level of an informer by refusing to discharge the grand jury, although entreated by several of the said jury so to do," and quoted his words to the grand jury in saying that he: ... understood "that a highly seditious temper had manifested itself in the State of Delaware among a certain class of people, particularly in Newcastle County, and more especially in the town of Wilmington, where lived a most seditious printer, unrestrained by any principle of virtue, and regardless of social order, that the name of this printer was..." --but checking himself, as if sensible of the indecorum which he was committing, added "that it might be assuming too much to mention the name of this person, but it becomes your duty, gentlemen, to inquire diligently into this matter," or words to that effect[...]Chase defended himself by stating that if he was aware of a federal law having been broken, it was his duty to bring it to the attention of the court.

"[16] He gave one of the closing arguments of the trial, in which he stated, "Give any human being judicial power for life, and annex to the exercise of it the kingly maxim 'that he can do no wrong,' you may call him a judge or justice, no matter what is the appellation, and you transform him into a despot.

In 1801, John and Richard Penn, heirs of William, brought a federal lawsuit seeking compensation for the uncultivated lands of Delaware which they claimed they were entitled to as former proprietors.

The damages they sought were allowed under the Midnight Judges Act signed into law by President John Adams before the end of his term.

The Penns were represented by Jared Ingersoll, Joseph McKean (son of Thomas), and Moses Levy; the state of Delaware was represented by Caesar A. Rodney, James A. Bayard Sr., George Read Jr., and state Attorney General Nicholas Van Dyke Jr. Presiding over the case was U.S. Judge Gunning Bedford Jr. and Justice Samuel Chase.

Prominent abolitionists and Underground Railroad conductors Thomas Garrett (a close friend and ally of Harriet Tubman) and John Hunn were put on trial for violating the Fugitive Slave Act.

Justice Taney's instructions to the jury left little choice but a conviction: To entitle the plaintiff to a verdict in this case, it is necessary for him to have proved property of the slaves.

Upon hearing Taney's punishment, Garrett gave a speech to the courtroom in which he stated: I now pledge myself, in the presence of this assembly, to use all lawful and honourable means to lessen the burdens of this oppressed people, and endeavour, according to ability furnished, to burst their chains asunder, and set them free; not relaxing my efforts on their behalf while blessed with health and a slave remains.

[...] After mature reflection, I can assure this assembly it is my opinion at this time that the verdicts you have given the prosecutors against John Hunn and myself, within the past few days, will have a tendency to raise a spirit of inquiry throughout the length and breadth of the land, respecting this monster evil (slavery), in many minds that have not heretofore investigated the subject.

[19]After the trials, Garrett corresponded with Harriet Beecher Stowe, and four years later she used the events as the inspiration for some of the scenes in her novel Uncle Tom's Cabin.

Hunn served with the Freedmen's Bureau, and his son was elected Delaware governor and oversaw state approval of the 13th, 14th, and 15th Amendments to the Constitution.

Bayard later defeated Wales again in 1850 when he won election to the Senate, where he became one of the fiercest critics of the loyalty oaths[20] and where he voted to acquit President Andrew Johnson in his impeachment trial.