From Libertarian Wiki

The Great Depression is usually considered to have begun with the October 1929 stock market crash and lasted until well into the 1930s, or even until World War II. It was not the only economic depression in American history; other depressions had occurred several times, but since the Great Depression it has been common to call economic slumps recessions rather than depressions. Murray Rothbard asserts in his book America's Great Depression that the statist responses to the stock market crash by presidents Herbert Hoover and Franklin D. Roosevelt prolonged the Great Depression; another popular assertion points to the role of the Federal Reserve.