After the atomic bombings of Hiroshima and Nagasaki on August 6 and 9, 1945, surrender quickly followed. The Japanese communicated their intention to surrender on August 15 Japan time, which was the evening of August 14 in the United States. While the official U.S. date for V-J day was the date of the surrender in Tokyo Harbor, September 2, V-J Day was celebrated in the United States the night of August 14 and August 15. The newspaper shown here is the Milwaukee Journal, August 15, 1940.

US Navy photo, via Wikipedia.

Scenes such as the one shown here in New York were common around the country.  (The photo shown here is a public domain picture taken by an employee of the U.S. Navy.  It is not the iconic copyrighted photo of the same scene that appeared in Life Magazine.)  The Milwaukee paper, for example, reported that thousands of families spontaneously gathered in downtown Milwaukee, their car horns blaring.