Where's the courthouse, where the surrender took place? The surrender occurred in the village of Appomattox Court House, Virginia in a private home owned by the McLean family. In Virginia many of the towns which were county seats were called "Court House". The building is spelled courthouse (one word) and the town is Court House (two words).
Where was the treaty signed? There was no treaty signed to end the Civil War. The surrender at Appomattox Court House was a military surrender of an army which was surrounded. The Confederate government never surrendered and even had it wanted to the United States government would likely not have accepted. To do so would have legally acknowledged the existence of the Confederate States of America and would have legitimized it and given it certain legal status internationally. Treaties are between two nations and the U.S. would never concede the legal existence of the Confederacy - even though it had a government, armies, taxes and all the trappings of a modern government.
What happened to Confederate President Jefferson Davis? Davis was captured by Federal troops on May 10th in Irwinville, Georgia. He was held prisoner at Fort Monroe in Virginia for approximately two years while the U.S. government tried to build a case to try him for treason. He was ultimately released without a trial. Many scholars feel that the U.S. government was concerned that if they tried Davis for treason it would lead to a case on the constitutionality of secession.
Who was present during the surrender meeting? Over the years a great deal of time and research has been done by National Park Service Curators and Historians in an attempt to accurately answer this question. In addition to who was in the room, much effort has been expended to determine how the room was furnished, how each of the officers were dressed, and etc. In 2002 a new Park Handbook was created which contains much of this information. Along with the "Handbook," the Park Service contracted with a well known Civil War Artist, Keith Rocco to create an image of the surrender meeting based upon all of the research which had been done. The handbook and the print are both available through the park bookstore (434-352-2136).