The end of the war: Associated Press
When Confederate Gen. Robert E. Lee surrendered to Union Lt. Gen. Ulysses S. Grant in a farmhouse parlor in Appomattox Court House, Virginia, on April 9, 1865, standing with other war correspondents in the front yard was William Downs MacGregor of The Associated Press.
The names of many AP Civil War correspondents, along with their original manuscript reports, have been lost. But those like MacGregor, whose names were occasionally printed beneath their dispatches, are remembered for delivering disciplined and restrained accounts in an era when reporting was often laced with shrill and sectarian opinion.
The Associated Press had been organized as a newspaper cooperative in 1846, just two years after the first successful telegraph message had been sent. During the war, the AP and most big city papers utilized the thousands of miles of ever-expanding telegraph lines to revolutionize war reporting. For the first time, battlefield victories and defeats could be transmitted and even printed within a day.
Competition was often fierce: When Washington officially confirmed Lee's surrender, one northern paper boasted it beat AP's telegraphic report by 15 minutes. News of the Union victory spread within hours to most major cities in the North and was published there the following day. (Southern papers, for the most part, had by this time been taken over by Union loyalists, had their presses destroyed, or could no longer publish for want of ink and paper.)
From the Associated Press and ABC News