Why did the Great Depression happen in the U. S

The banking system, Reduction in purchases, overpopulation of crops, stock market crashing, civilian conservation corps, agricultural adjustment act, rural electrification, social security, etc.

The depression was caused by a number of serious weaknesses in the economy ... America's "Great Depression" began with the dramatic crash of the stock market on "Black Thursday", October 24, 1929 when 16 million shares of stock were quickly sold by panicking investors who had lost faith in the American economy.