Final answer:
John Wilkes Booth assassinated President Lincoln at Ford's Theater in Washington, D.C., on April 14, 1865, which led to deep national mourning, particularly in the North and amongst African Americans.
Step-by-step explanation:
President Abraham Lincoln was assassinated by John Wilkes Booth, a Confederate sympathizer and well-known actor, on April 14, 1865. Just five days after the South's surrender, Booth carried out his attack while Lincoln was attending the play Our American Cousin at Ford's Theater in Washington, D.C. This event was part of a larger conspiracy to disrupt and challenge the Union government, potentially reviving the Confederate cause. Booth's actions on that fateful night led to his own death when Union troops tracked him down and found him in a barn in Maryland. His death on April 26, 1865, concluded the intensive manhunt. The assassination provoked widespread grief in the North, particularly among African Americans, for whom President Lincoln symbolized the promise of freedom and the end of slavery.