The location of General Lee's surrender was Appomattox Courthouse in Virginia. If all that you need is a date, that occurred in April of 1865. The book Across Five Aprils says that it happened on April 5, which is odd, because the historical date for the surrender is April 9, 1865.
The terrible news that Nancy gave Jethro after the celebrations was that President Abraham Lincoln had been assassinated.
Jethro is devastated by the news of Lincoln's death. The person that shows up shortly after is Shad. Shad was the local school teacher before the war, and Jethro especially looks up to him. Jethro considers him one of the smartest people that he knows. Shad eventually reveals to Jethro that he will be going back to college and bringing Jethro with him.