Great Depression, period of U.S. and world economic depression during the 1930s that was immediately precipitated by the disastrous stockmarket collapse on Wall Street on Black Friday, Oct. 29, 1929. This heralded a period of high unemployment, failing businesses and banks, and falling agricultural prices. Millions of workers were unemployed during the period (some 16 million in the United States alone in 1933). There were many causes of the depression: Easy credit had led to widespread stock speculation; the world had not completely recovered from World War I; U.S. economic policies under President Herbert Hoover had created domestic overproduction and less foreign trade. Franklin D. Roosevelt, elected president in 1932, brought in the New Deal measures, but full recovery of the economy occurred only with the beginnings of defense spending immediately prior to World War II.
See also: United States of America.